Use the buttons below to view errors in any category. You can make any errors visible by clicking on their title or their corresponding checkbox.
Error_checker.exe, the program you can use to automatically scan your log for errors, can be found here
User-interactive error editing is now also supported, please see here for more info about editing.
Post your compile log here to have it checked for errors. You may also search for any errors by entering a search query and uncheck 'this is a compile log' to search for non-compile errors.
This is a compile log
Description:
This means a texture is aligned to its face at 90 degrees. This is because the "align"-settings for that face are setup wrong. 
Solution:
Either use the problemchecker (alt+p) to fix the error, or do it yourself by selecting the face or brush, and then go to the texture-application tool and select 'align to face' or 'align to world'. if that doesn't work, your brush might be too broken (invalid) to repair and you'll have to repair/delete it manually.
See also:
Reference: What are invalid solids?
Description:
When this error is seen various file open dialogs (sound, models) make Hammer crash. The cause can be found in the absence of filesystemopendialog.dll
Solution:
You can recreate this file by:
See also:
HL2 WIKI about this error Thanks to The Odd One for pointing this out
Description:
Hammer does not have enough memory loading all the brushes in your mapfile. This can be caused by either a BOG, excessive, ENOURMOUSLY HUGE map, or some error in the vmf structure of your mapfile which caused Hammer to go into a loop. Causes are using quotes or curly brackets (" or { } ) in entity names, values or outputs (mind: game_text), which will break your map's datastructure.
Solution:
you have three hopes: [list] [*]A backup file (mapname.vmx) should be in the same directory as your mapfile, rename it to vmf to open it) [*]Hammer has autosaves (atleast if you have in enabled). You can try opening the autosaves, look under the Hammer options to find the autosave path [*]A long day trying to try to repair your map with Notepad. You can try three things:
If you really can't figure it out, and you have spend a lot of time on your map already, you may also send me the map and I will take a look and see if i can fix it.So far I have been able to repair all maps people have sent me, so bring em on!
See also:
WIKI: vmf structure
vmf structure
Description:
One of your brushes is invalid. Just remember these three rules and you should be fine:
Solution: Fix the brush or delete it.
See also:
Reference: Invalid solids
Description:
Hammer always checks if there's an info_player_start in your map (it's the place the player will be spawned on start), even with mods that don't require an info_player_start (but eg info_player_terrorist).
Solution:
Either ignore the error or place an info_player_start somewhere in your level. Even if your mod requires an info_player_start, the map will still work, but the player will be spawned at the exact center of the map. Please note that if your map doesn't have any entities, it may leak, causing other problems.
Description:
Spotlights usually throw their light in a cone. you just can't make a cone thats larger than or equal to 2*90 degrees (this is a purely mathematical restriction). This isn't dangerous or anything, when your map is compiled the values will automatically be lowered to the maximun allowed. It is merely a warning.
Solution:
Go to the specified entity and lower its angle value. for larger angles you should use the normal light-entity, or multiple light_spots.
Description:
This error means the specified entity has wrong outputs or inputs. Either it is targetting a non-existing entity, trying to tell another entity to do something it isn't programmed to be able to do or just using the wrong output.
Solution:
Go to the outputs tab of the entity and fix any values in RED.
See also:
Entity input/output system
Description:
You need to set the color depth in Windows to atleast 32 bits, for the models to appear correctly in the browser.
Solution:
Right-click anywhere on your desktop, select 'properties', go to the 'settings' tab and set the color quality to 32 bits. Outdated drivers may also be the cause.
Description:
You have set the render mode to wireframe.
Solution:
You need to set the camera mode to 3d-textured. Simply press on the word 'camera' in the 3d window and select '3d textured'.
Description:
Nothing gets rendered in the 3d view, may be caused by a bug where no default camera is made in Hammer. Other causes are drivers or other interfering soft/hardware.
Solution:
First try to create a new camera view (click the camera button, then drag a line in one of your 2d views). If that doesn't work, and you made sure you aren't just looking at black textures or into the void, you may need to restart Hammer. OpenGL is a real bitch if you switch between programs that aren't programmed exactly like they should. As as last resort, try updating your drivers, or reinstalling SourceSDK.
Description:
One (or more) brushes in your map were invalid and removed. Hammer doesn't like loading invalid brushes, so it just deletes them.
Solution:
Nice as that is (you can't do anything about it when you actually see the error) it's up to you to find the brush(es) it deleted. Since the brushes are already deleted, there is no need for finding invalid solids, they are already gone. Tip: Check for illegal brushes before you close hammer and save your map, to make sure you don't end up with invalid solids in the mapfile.
See also:
Reference: What are invalid solids?
Description:
At the end of the compiling process the BSP file is copied from the directory your vmf file is in to the game/maps directory so it can be played. This error means it couldn't find the BSP to copy it.(the message Windows returns may vary on it's language) The cause is usually some fatal error in vbsp.exe (the program that generates the bare bsp-file) so check for other errors in your log. The other cause is some invalid setup of directories, or bad mapnames, too long pathnames etc. In which case you should also see the effects further upwards in the log (something like the other programs not being able to load your map). For mapnames, remember to avoid any strange characters, like brackets, dots, commas and spaces. try to build your mapname out of characters ( a-z ), numbers ( 0-9 ) and the underscore ( _ ) only. The exact cause is usally findable in the logfile. Remember this error is not a cause of your map to not compile, it is merely a sign that your map didn't compile.
Solution:
Check your logfile for errors, check your directory setup or rename your map.
See also:
Logfile-checker (see search above)
Description:
Half-life couldn't open your map. Did you recieve any errors in the compile process? Got your paths set up right? Maybe your map is empty?
Solution:
Scan your compile-log for other errors and fix those
See also:
Logfile-checker (see search above)
Description:
As you create bigger maps, the compile process will take longer and longer. You can prevent a lot of this by optimizing your map. By telling the compile tools what to ignore and how to work, you can seriously decrease the time needed to build your map.
Solution:
Optimize your map. Use func_detail and hints to speed up the compile process. Alternatively, you can use visgroups or cordon tools to only compile a part of your level. This is great for checking only a part of your level. Lastly, you can set vvis.exe and vrad.exe to [-fast], so they do a worse job (not for final compiles!) but much faster than before.
See also:
Optimization tutorial
WIKI: Optimization
Controlling what to compile
Reference: Compiling theory
Description:
These warnings can be completely ignored, they have nothing to do with your map (but with crappy programming by Valve!).
Solution:
Become a Valve programmer and fix the problem.
Generally, this error may be ignored
Description:
One of your brushes is smaller than the smallest allowable brush-size. This size (when it will be warned about) is specified in the compiler, but can be changed (it's an option for vbsp, [ -micro #] default is 1.0 cubic unit).
Solution:
Find the brush using 'view->go to brush number' in Hammer or ctr+shift+G in Hammer and enter the specified brush number. Either delete it, or enlarge it, whatever you desire. If you need small brushes, you may be better of with models instead.
See also:
WIKI: Vbsp
The affected object may not work/appear properly
Description:
You have tied a displacement to an entity. Displacements aren't supposed to be entities. (they don't need to be func_detail, vvis.exe ignores them anyway)
Solution:
Find your displacement and de-entify it. The easiest method to find it in a big map is to select all displacements at once (select the "displacements\ visgroup (in the visgroup-window to the right in Hammer), then press "mark") in the ignore group mode (button "IG"). Now tie all of the displacements to an entity, and "to world" them again right after that while they are still selected.
This error will cause your map to fail compiling completely
Description:
Your map is too big (you have brush(es) too near to the edge of the grid) or you have invalid brushes.
Solution:
If the problem-checker in Hammer (alt+p) doesn't find any offending brush(es), and you can't see brushes near the edge of the grid, you should use the cordon tools or visgroups to find them.
See also:
Reference: Finding the unfindable
Reference: Invalid solids
This error will cause your map to fail compiling completely
Description: Usually preceded by some coordinates, the best explanation I can give at the moment is that this is caused by certain models (a b0rked subpart). In particular the \"/wasteland/InteriorFence002d.mdl\"-model. I\'ve also heard small panes of glass and some other (even self-made) models can cause this error to occur, as do some freaky regular brushes. This error can also be caused by bad displacements. If it is displacements they may fail to collide with vehicles and physics objects on the triangles that are causing a problem. Parts of the displacement may still work others may not.
Solution:
You can look for ages to find the model causing the problem, after hiding all your models first and see if that is causing your problem. Once found, you can decide to reconstruct that model, there doesn\'t seem to be a real error in the model itself though. In other words, leave it be, it won\'t hurt you. Unless you bite first! It may be the case that the game will not load the map because of this error. It would present you with a pup-up with the beloved memory error. The displacement problem as of right now has only 1 solution and it is to delete the displacement. If its a brush, find it with Cordon Tools and delete it.
The affected object may not work and/or cause general errors
Description:
You've tried to use a water texture which should only be placed in the map automatically by the compiler, or the water-texture you did use has an invalid bottom-texture. Invalid materials usually end in _beneath or _bottom or _dx* .
Solution:
There will be a matching texture without those suffixes which you can use instead. Try another water texture.
See also:
WiseMx's list of water examples
The affected object may not work/appear properly
Description:
One of your info_overlays is spanning more faces than the maximum of 64. This number is based on the faces after bsp cutting, so it might look allright in Hammer but doesn\'t work ingame.
Solution:
Check each overlay in your map, and make sure it doesn\'t cover more than 64 faces. Allthough easier said than done, you must try to find the overlay in Hammer (where you can only guess where your faces are cut) so its best to check big (stretched) overlays first, and also make sure you have no world brushes cutting each other up near these overlays (eg. near stairs, or when you use a small lightmap scale). The use of func_detail will stop that.
See also:
Reference: Finding the unfindable
This error will cause your map to fail compiling completely
Description:
One of your brushes has a face with a bad normal (a normal is a oriëntation of a texture on a face).
Solution:
First see if the problemchecker in Hammer can find and fix it. If it can't, find the brush and fix it manually (usually it's best to delete it and start all over) or select the brush and "align to face" it in the texture-tool.
See also:
Reference: Finding the location of errors
This error will cause your map to fail compiling completely
Description:
One of your brushes has no visible sides. My best guess is that this is caused by an invalid brush.
Solution:
Try Hammer's problemchecker (alt+p) to find and fix it, otherwise you'll have to find the brush and use vertex manipulation or a good ole delete.
See also:
Reference: Finding the cause of errors
Reference: Invalid solids
The affected object may not work and/or cause general errors
Description:
Your map is too big (you have brush(es) too near to the edge of the grid) or you have invalid brushes.
Solution:
If the problem-checker in Hammer (alt+p) doesn't find any offending brush(es), and you can't see brushes near the edge of the grid, you should use the cordon tools or visgroups to find them.
See also:
reference: Finding the unfindable
Reference: Invalid solids
The affected object may not work and/or cause general errors
Description:
You have an model-based entity (prop_something) without a model specified.
Solution:
To fix, delete it or give it a model. It can be hard to find, and if you really cant find it, use this trick: open your map (.vmf) in wordpad, and search for the string:
"model" ""
replace it with something you never used in your map, eg.
"model" "somenameineverusedforanentity"
Save the file, and open it up in hammer again. using 'entity report' in Hammer, you can search for the string "somenameineverusedforanentity" and your entity comes up. Alternatively, you may delete the entire entity, by removing it entirely:
entity { "some stuff" "more stuff" "model" "" "origin" xx xx xx" editor { "color" "220 30 220" "visgroupid" "2" "visgroupshown" "1" } } would be what you can delete. after the last "}" the next entity will be specified. Remember to delete the entire entity, and only that one, or your map may get broken. As a precaution, you should always backup your map before editing it in notepad.
The affected object may not work and/or cause general errors
Description:
This error means you have a brush with coplanar planes (aka an invalid brush). simply put, two sides of the same brush aren't allowed to be on the same plane.
Solution:
The fix is to repair the brush, by either merging the two brushsides or moving them so they aren't on the same plane anymore.
See also:
Reference: Invalid solids
The affected object may not work and/or cause general errors
Description:
A degenerate triangle is a triangle with no area. for instance, when two of its points are at the same place or all three on one line. I believe this error only affects displacements, but i am not entirely sure. It also seems to be used in collision data (for the displacements?)
Solution:
Find the triangle (using the coordinates, each set represents a vertex) and see if you can fix it (e.g. by moving one of the vertices, or deleting it. For displacements, you may need to destroy the displacement and start all over if you can't seem to fix it. It wont harm you if you leave it, but make sure the area doesn't look weird because of it. (holes in the displacements, overly stretched textures)
See also:
Finding coordinates
Generally, this error may be ignored
Description:
Your map has a node without a volume. (a node is what a clipnode was in hl1, in other words a volume denoting where the player can get to and where not.)
Solution:
Unless you just did some vertex-manipulation or placed static props in a wall, or added a funky new displacement, you shouldn't hunt this error down, as it may take you ages to find, unless you get strange effects in your map. Just fix (simplify) the awkward gemetry if you find it. May also be the sign of an invalid brush, or simply vertices offgrid (unlikely?).
See also:
Reference: Finding the unfindable
Generally, this error may be ignored
Description:
Your map has a node with an infinite size. (a node is what a clipnode was in hl1, in other words a volume denoting where the player can get to and where not.)
Solution:
Unless you just did some vertex-manipulation or placed static props in a wall, or added a funky new displacement, you shouldn't hunt this error down, as it may take you ages to find, unless you get strange effects in your map. Just fix (simplify) the awkward gemetry if you find it. May also be the sign of an invalid brush, or simply vertices offgrid (unlikely?).
See also:
Reference: Finding the unfindable
Generally, this error may be ignored
Description:
You have used the ORIGIN texture on a brush that isn't allowed to have the ORIGIN texture. ORIGIN is only allowed on parts of brushbased-entities, and only on brushes that have all sides with ORIGIN.
Solution:
Simply replace the offending ORIGIN textures.(there's a replace option in the texture browser menu) On a side note, if you turn on helpers (the diamond shaped button in the right, top bar) you can specify an origin without the use of origin-brushes. much easier and safer. The origin-brush is just there for compatibility with hl1 maps, you shouldn't use it for hl2 maps.
This error will cause your map to fail compiling completely
Description:
You can specify for each cubemap which faces should be using it. However, each face can only have one cubemap attached to itself this way. If you want the face to use multiple cubemaps you shouldn't tie them statically to cubemaps this way, but split the face (into multiple brushes).
Solution:
I hope you can find out by the name of the texture which face vbsp is talking about, because that's the only reference you have. No nifty stuff will help you find the problem, you have to check each texture or cubemap individually to find it. Or just leave it, as far as i know it defaults to one of the two env_cubemaps anyway, so it wont harm you one bit if you leave it.
Generally, this error may be ignored
Description: You aren't allowed to have the "tools/nodraw" texture one a displacement.
Solution: There are two possible causes, you accidently covered a displacement face in nodraw or you accidently made a hidden face a displacement. In order to fix it in either cases, uncheck the "auto" visgroup, then check only the "displacements" visgroup. Now, look round the map see if nodraw is anywhere you wanted a real texture. If found open the material browser and find and replace the nodraw texture with any other texture. If there's no vibisible displacement faces with nodraw you'll probably want to destroy them. Open the material browser, check "Only show used textures", select NoDraw and press "Mark". Open up the face edit sheet, and click "Destroy" on the displacement tab.
See also: Reference: Finding the unfindable
The affected object may not work/appear properly
Description:
See Max_map_texinfos
This error will cause your map to fail compiling completely
Description:
You have too many brushsides in your map. The mentioned brush is simply the first one that didn't fit in the buffer. See Max_map_brushsides
This error will cause your map to fail compiling completely
Description:
You have a prop_static outside the map, or you have a big leak.
Solution:
Delete the entity, or fix the leak.
See also:
Reference: Leaks
WIKI: leaks
This error will cause your map to fail compiling correctly
Description:
You have a leak. A leak is a hole in your map that exposes any entity in your map to the void (the black space outside your map).
Solution:
Fix the leak.
See also:
Reference: Leaks
WIKI: leaks
This error will cause your map to fail compiling correctly
Description:
(from Jeff Lane, Valve) "VBSP does cleanup of edges where func_detail geometry meets world geometry to avoid getting visual cracks. One of the ways it does is this by elminating t-junctions. It sounds like you may have hit a limit of the number of those cleanups in the level.
Solution:
If that is the case, you could fix the problem by reducing the number of func_detail brushes in the level, especially ones that touch non-detail geometry. It's probably a sign that you have too much complex brush geometry in the level, and would benefit from having some of it be model geometry instead."
See also:
WIKI: making models out of brushes with XSI
This error will cause your map to fail compiling completely
Description:
You have used (created yourself?) a model without the data compiled in it for it to become a non-static entity. These kind of models can only be used on prop_statics, unless you recompile them with the neccesairy data.
Solution:
Find them using the coordinates, or simply recompile the model with the appropriate data
See also:
Find coordinates in a map
Compiling models
The affected object may not work/appear properly
Description:
You shouldn't use this texture, but this one: glass/glasswindowbreak070a. The b-texture is used after the glass is broken, so you should never put it into your map manually. Sometimes this error occours and you dont have this texture anywhere in your map. Probably being some strange bug, might as wel leave it, it seems to cause no harm.
Generally, this error may be ignored
Description:
See Max_map_portalverts
This error will cause your map to fail compiling completely
Description:
A render order determines which overlays are drawn on top over the others (or under). These render orders are simple numbers, ranging from 1-3. Other numbers are invalid, causing this error.
Solution:
f this error is accompanied by insanely huge numbers, it is most likely a badly placed info_overlay (atleast it was in my case). These entities don't like to be placed on the edge of a brush. If even that is not the case, try to open the map in a texteditor and look for the numbers. They may be caused by a b0rked map, or something along those lines.
See also:
Finding the unfindable
This error will cause your map to fail compiling completely
Description:
You have too many planes (a plane is an angle for a brushside to exist) in your map. The mentioned brush is simply the first one that didn't fit in the buffer. See Max_map_planes
This error will cause your map to fail compiling completely
Description:
Displacements can only have four sides, no more, no less.
Solution:
Find your displacement (you'll have to check each one in your level) and recreate it so it has four sides again. You may need to be creative with some vertex manipulation for some shapes you want to create with displacements.
See also:
Finding the unfindable
This error will cause your map to fail compiling completely
Description:
Either you have placed your sky_camera in a brush, or your map has a leak.
Solution:
Use entity report to find the sky_camera and move it, or in case of a leak, fix the leak.
See also:
3d skybox tutorial
Reference: Leaks
WIKI: leaks
This error will cause your map to fail compiling completely
Description:
One of your areaportals touches either too many, or to few areas. Possible causes are: -areaportals touching/intersecting each other (this causes them to touch more than two areas) -areaportals that dont seal an area ( you can move from one side of the areaportal to the other side, without crossing world geometry or other areaportals). This is also regared as a leak.
Solution:
The fix would be to move your areaportal(s) around so the above situations don't occur. You may need to read up on the usage of areaportals if you do not understand the problem. I suggest you find your areaportals using it's brushnumber
See also:
Areaportals
WIKI: Func_areaportal
The affected object may not work and/or cause general errors
Description:
You have too many vertices in your map (point from which brushes are made). In other words, your map is too big or too detailed.
Solution:
Delete or simplify some of your brushes. Perhaps you can convert parts of your map into brushes, or in case of SP maps, divide the map up into multiple parts with a level change?
See also:
Max_map_verts
This error will cause your map to fail compiling completely
Description:
You have a leak. A leak is a hole in your map that exposes any entity in your map to the void (the black space outside your map).
Solution:
Fix the leak.
See also:
Reference: Leaks
WIKI: leaks
This error will cause your map to fail compiling correctly
Description:
See Max_map_models
This error will cause your map to fail compiling completely
Description:
You have entered a skybox texture which doesn't seem to be valid. Make sure you don't specify the last three letter (_UP, _DN, etc) of any skybox texture you use. You may also need to fix your vmt files if they are broken. This error comes up for every map since the HDR update. (you can tell if the tools start nagging about $hdrbasetexture). See below for a fix, though it is not neccesairy. It only affects the default cubemaps (the reflections that are saved to your map before you buildcubemaps your map) and HDR (may be a problem if you use it), as long as there is no problem with the name of the skybox or it's vmt files.
Solution:
Fix $hdrbasetexture errors first
WIKI: Skybox
The affected object may not work/appear properly
Description:
Vbsp expects you to use a HDR skybox, even though your mod likely doesn't support one. TBH it's quite awkward Valve own maps aren't HDR, while their tools expect them to be. Meh.
Solution:
Either make a HDR skybox, change your skybox to a HDR one or ignore this error. See below for a detailed fix.
See also:
WIKI: HDR skybox
How to fix this error
The affected object may not work/appear properly
Description:
I don't know the cause, probably has to do with displacements touching too many other displacements.
Solution:
Check your displacements for anything wierd or out of place.
See also:
Reference: Finding the cause of unknown errors
The affected object may not work and/or cause general errors
Description:
You have too many/too big displacements
Solution:
Destroy, or simplify, some of your displacements
See also:
MAX_MAP_DISPINFO
This error will cause your map to fail compiling completely
Description:
One of your entities should be brush-based, but doesn't have a brush tied to it. This can happen eg when you tie the brushes of this entity to another entity in "Ignore groups"-mode.
Solution:
Find your entity (use entity report in hammer to filter for the entities class and/or name) and delete it or tie it to a brush
See also:
WIKI: Entity report
The affected object may not work and/or cause general errors
Description:
One of your areaportals touches too many areas. The probably cause is one or more areaportals touching/intersecting each other or world brushes that seperate atleast two areas (this causes the areaportals to touch more than two areas).
Solution:
The fix would be to move your areaportal(s) around so the above situations don't occur. You may need to read up on the usage of areaportals if you do not understand the problem. I suggest you find your areaportals using it's brushnumber
See also:
Areaportals
WIKI: Func_areaportal
The affected object may not work/appear properly
Description:
The amount of detail props (the grasses and such that automatically appear on displacements with some textures) has exceeded the maximum number of allowable detail props.
Solution:
Either reduce the amount of textures/displacements which cause these props to appear, or edit the texture's vmt's to decrease the number of detail props those textures emit.
See also:
WIKI: Displacement grass
WIKI: Detail props
This error will cause your map to fail compiling completely
Description:
One of your textures is scripted to emit detail props (the grass thingies that appear on displacements), but the detail props specified are not defined in the mod's data files.
Solution:
Usually this error is caused by mindlessly porting textures from other mods, without porting the detail props file. The fix is to either get these detail props from that other mod, or fix the texture so it emits detail props that exist in the current mod.
See also:
WIKI: Displacement grass
WIKI: Detail_props
The affected object may not work/appear properly
Description:
The cause for this error is using multiple (incompatible) tool-textures on the same brush. Apart from HINT and SKIP there aren't much combination of tool-textures allowed on the same brush, so any other combination is a possible cause. Tool-textures are the 'tools/' textures you can find using the texture browser in Hammer, and that have a special meaning.
Solution:
You will need to find the brush(es) with these tool-textures and replace those textures. The easiest way to find the source of the error is to hide all visgroups except for the visgroups which are for tools textures and then just look around the map in 3d textured mode.
See also:
WIKI: Tool textures
Thanks to crazypip666 for submitting.
This error will cause your map to fail compiling completely
Description: This error is usually followed by something like this:
Leaf 0 contents:(may vary) Leaf 1 contents: CONTENTS_SOLID (may vary, e.g. CONTENTS_WATER) viscontents (node 0 contents ^ node 1 contents): CONTENTS_SOLID (ditto) This means that none of the brushes in leaf 0 or 1 that touches the portal has CONTENTS_SOLID Check for a huge brush enclosing the coordinates above that has contents CONTENTS_SOLID Candidate brush IDs: [none or more brushnumbers]
Usually, this error is caused by a leak, so fix it if it is. If it isn't, there is a (group of) brush(es) that is/are giving vbsp.exe a hard time to figure out your level. I don't know the details (apart from the vague description in this error) but usually turning entities to world brushes or vice-versa helps to fight the problem. Hell, just cutting a brush in two once helped me fight this problem.
Solution:
Find the given coordinates (or if a brush number is given search for the brush number) and see what you can do to to simplify the area (like turning brushes to func_detail). You should also check to see if the brushes are overlapping at any point.
See also:
Finding brushnumbers and coordinates
The affected object may not work and/or cause general errors
Description:
This error means you have a func_occluder (by the name of "some_name") that is touching an areaportal or is inside a brush that's touching two area's. ( An area is a part of your map closed off by a areaportals and world-brushes)
Solution:
Move or delete the occluder or areaportal(s).
The affected object may not work and/or cause general errors
Description:
Pretty obvious, an func_areaportal(window) can only consist of one brush.
Solution:
Make multiple brushes multiple func_areaportal(window)s, or make different windows in a wall the same areaportal(window) (they can go through walls if needed).
This error will cause your map to fail compiling completely
Description:
You have used the wrong model with the wrong entity.
Solution:
Either change the model, or the entity (eg. like it says in the error, use a prop_physics, prop_dynamic or prop_physics_multiplayer or whatever the compiler tells you you should use). Just as a thumb rule: -anything that can be picked up is prop_dynamic or prop_physics(_multiplayer) -anything thats completely static is prop_static (you may alsop recognise these with invisible backsides) -anything with dynamic shapes (eg. bodies, matrasses) is prop_ragdoll There are exceptions offcourse, as allways.
See also:
WIKI: Prop types
The affected object may not work/appear properly
Description:
You have used the wrong model with the wrong entity, or there is another reason the model couldn't be loaded, like an invalid location, errors in the file etc.
Solution:
Either change the model, or the entity (eg. like it says in the error, use a prop_physics, prop_dynamic or prop_physics_multiplayer) or whatever the compiler tells you you should use). Just as a thumb rule: -anything that can be picked up is prop_dynamic or prop_physics(_multiplayer) -anything thats completely static is prop_static (you may alsop recognise these with invisible backsides) -anything with dynamic shapes (eg. bodies, matrasses) is prop_ragdoll There are exceptions offcourse, as allways.
See also:
WIKI: Prop types
The affected object may not work/appear properly
Description:
You have too many brushes in your map (more than 8192) The given brush is just the first one to go over the limit, it's properties in this error are useless
Solution:
Delete some brushes, turn some of them into models for area's high in detail. For singleplayer maps, you may decide to add a level transition and split the map into multiple levels. Multiplayer maps that reach this limit are probably too big for multiplayer anyway.
See also:
MAX_MAP_BRUSHES
This error will cause your map to fail compiling completely
Description:
vbsp crashes upon building the physics collision data, windows may bring up the error pop-up
Solution:
check to see if you have tiny and/or overlapping displacements most likely in a skybox. Replace them with func_detail or models.
This error will cause your map to fail compiling completely
Description:
Vvis.exe cannot find the portalfile, a file that vbsp.exe creates which specifies the location of portals and leafs. Usually because of a leak or other fatal error (see further upwards in your log) in the vbsp process, but may also be because your directories are set up wrong.
Solution:
Check your logfile for other errors (mainly leaks), and/or check if you have your directories set up right.
See also:
The compile process
Reference: Leaks
This error will cause your map to fail compiling correctly
Description:
I think you have hit some kind of limit in the vvis process, considering the process (vvis.exe) I suppose this is visleafs, if so, optimizing may work. You may also try to reduce the amount of props in your map, (grasses), I've heard this can help too.
Solution:
See above
See also:
Optimizing tutorial
HL2 WIKI Optimization
This error will cause your map to fail compiling correctly
Description:
Your map has too many portals. (your portals is x, the max is 32768)
Solution:
Optimize your map (tie brushes to func_detail) to reduce portals. You may even have to decrease the size of your map.
See also:
Using func_detail
MAX_MAP_PORTALS
WIKI: Optimization
This error will cause your map to fail compiling completely
Description:
(I think) vbsp.exe has made a concave leaf (or in other ways invalid) that can see into itself. I've also heard about this being caused by overlapping brushes or brushes that are off-grid (thuss causing offgrid visleafs). Allthough i find this unlikely, I am not sure if it isn't, so keep those possibilities open too.
Solution:
The solution is to simplify your leafs (func_detail) as much as possible to avoid this error, but usually (or sometimes) you will find no bad things come from it and your map runs as it should. If you got unexpected low FPS somewhere, this may be the cause. Finding it may be hard, and usually ends up in using cordon tools or just not doing it at all. First look at complicated parts of your map, try to use glview glview to find it.
See also:
how to use glview
WIKI: glview
The affected object may not work and/or cause general errors
Description:
One of your leafs is neighbouring too many other leafs. (the 'doorways' between leafs are called 'portals'). This causes vvis.exe to quit compiling your map. e.g. in the example picture, the center leaf would have 12 portals, and all other ones only one. 
Solution:
Find your leaf, and see if you can reduce the number of neighbouring leafs by adding world brushes or turning existing ones into func_detail (or clever placements of hints). Big leafs in the sky should also be avoided. As the error says, open your map in Glview to find the exact location of the portal. Contrary to what the error says, you need to use a different syntax for starting glview:
Drive:\path\glview.exe -portal X -portalhighlight \.gl
If you have problems using Glview, check the links below.
See also:
Reference: Using Glview
Optimizing can help against this error
WIKI: visleafs
WIKI: Glview
This error will cause your map to fail compiling correctly
Description:
One of your leafs is neighbouring too many other leafs. (the 'doorways' between leafs are called 'portals'). This causes vvis.exe to quit compiling your map. e.g. in the example picture, the center leaf would have 12 portals, and all other ones only one. 
Solution:
Find your leaf, and see if you can reduce the number of neighbouring leafs by adding world brushes or turning existing ones into func_detail (or clever placements of hints). Big leafs in the sky should also be avoided. As the error says, open your map in Glview to find the exact location of the portal.
See also:
Reference: Using Glview
Optimizing can help against this error
WIKI: visleafs
WIKI: Glview
This error will cause your map to fail compiling correctly
Description:
Vrad.exe is freaking out over some part of geometry in your map. Did you recently add any complicated/oddshaped brushes?
Solution:
Find the brush(es) vrad doesn't like and remove or fix them.
See also:
Reference: Finding the cause of unknown errors
The affected object may not work and/or cause general errors
Description:
A solid in your level has a face with no area. My guess is that vrad.exe is trying to create a lightmap for a face that doesn't exist. Maybe you have an invalid brush?
Solution:
First check Hammers problemchecker (alt+p). If that doesn't solve your problems, you can either ignore the error, or try to find it anyway using cordon tools. You would be looking for brushes which might be too complex. I wouldn't recommend the second option.
See also:
Reference: Finding the cause of unknown errors
Generally, this error may be ignored
Description:
I don't know the exact cause, but ive heard rumours that it can be caused by: -lightmaps not set to a legal size (power of 2) To check, select all brushes in your map and set them to a lightmapscale of 16, save to a different mapname and try to compile the map. If you still got the error, the cause lies somewhere else. -big displacements in combination with too small lightmapscale. (seems commonest) -invalid brushes -invalid displacements
Solution:
You may want to start by hiding all your displacements and see if the error persists. If it does, check every lightmapscale in your level first and if that won't help, use visgroups or cordon tools to break your level apart.
See also:
Reference: Finding the cause of unknown errors
This error will cause your map to fail compiling correctly
Description:
Your lights.rad has too many entries (there is a maximum of 128 entries) the rest will be skipped.
Generally, this error may be ignored
Description:
Vrad.exe did not have enough memory to finish it's task. There are two causes: 1) You are running low on memory (ram + pagefile). 2) Vrad.exe is chocking on some very complicated bit of your map, causing it to ask a lot of memory which doesn't exist (like infinite sizes).
Solution:
If you are running low on free memory (ctr+alt+del to see that) try increasing the pagefile if you aren't letting Windows take care of it. If not, use cordon tools to isolate the problemarea in your map (might be a broken brush, or simply too complex geometry) and see what you can do to fix it. Radosław Rak suggests using the custom compile tools (see below), as they dont seem to be troubled by this error. Dan Prati informed me that is mostly a problem with very large, open maps, or particularly detailed ones (or as part of an engine limitation to the total amount of lightmaps). Reducing the lightmap resolution on larger surfaces, or particularly complex objects, can fix this problem. If this is not acceptable, or does not fix the error, reducing lightmap resolution across the entire map may be necessary. This provides a solution when there is no single map element that is causing the error, and simply deleting map objects won't fix the problem.
See also:
Reference: Finding the unfindable
Amckern's custom compile tools
This error will cause your map to fail compiling correctly
Description:
You have too many (more than 32) differently named lights in your map. You can't have that many independantly switchable lights
Solution:
Remove some lights, or give a few the same name, or remove the names of some lights.
This error will cause your map to fail compiling completely
Description:
There's a face with too many different light styles of light shining on it. (more than six). For every switchable light (that is: any light that is named or has a custom appearance) shining on a face, vrad.exe makes a new lightstyle. Basically, it calculates how the face looks like when: -light 1 is on and light 2 is off -light 1 is on and light 2 is on -light 1 is off and light 2 is off -light 1 is off and light 2 is on I'm sure you understand how 6 switchable lights make 2 ^ 6 lightstyles, and how this enormous amount of memory has to be saved somehow. and limited.
Solution:
To stop this error, remove lights, dont give the light names unless you need to, make sure certain lights dont shine on the face (max_shining distance or by blocking it with brushes) or simply dont use that much switchable lights. Dynamic lights are not used by vrad.exe thus dont count. Lights with the same names are counted as the same lights. Find the location of the error using the coordinates.
See also:
Reference: Finding the cause of errors
The affected object may not work and/or cause general errors
Description: A degenerate face is a face with no area. for instance, when two of its points are at the same place or three vertices on one line. Rarely, this error can cause all the lighting in your level to become black. If this happens, you will have to track down the degenerate face. This is however rare, so only go after the face if your level turns completely dark.
Solution:
Don't try to fix this error, it will take you ages to find them in your level, and it wont harm you if you leave it.
Generally, this error may be ignored
Description:
Vrad.exe couldn't find lights.rad, a file used to determine which textures can emit light by themselves.
Solution:
Move to/make a new lights.rad in the right directory. You should search for the file in your mod's directory, most mods have one.
See also:
Lights.rad tutorial
The affected object may not work and/or cause general errors
Description:
Vrad.exe couldn't find lights.rad, a file used to determine which textures can emit light by themselves.
Solution:
Move to/make a new lights.rad in the right directory. You should search for the file in your mod's directory, most mods have one.
See also:
Lights.rad tutorial
The affected object may not work and/or cause general errors
Description:
One of the entries in lights.rad is invalid. Make sure when you edit this file you use plain text-editors, e.g. notepad, wordpad. DON'T SAVE MAKE-UP to this file as MS-Word (from office) will!
Solution:
Lights.rad tutorial
The affected object may not work/appear properly
Description:
This texture was listed twice in lights.rad. the fix is obvious, but not necessairy
Solution:
Lights.rad tutorial
Generally, this error may be ignored
Description:
This is vrad's way of saying a texture (face and its corresponding luxel(lightmap)) is aligned to its face at 90 degrees. This is because the "align"-settings for that face are setup wrong. 
Solution:
Find the face using the coordinates. You will notice a very overstretched appearance of the texture belonging to the offending side. If you can't find it, you must select the entire brush, if you can find the exact face, just select that face in the texture application tool. When you are in the texture application tool, notice the "align to face" and "align to world" tickboxes. Try the one that isn't currently checked, or both. If they don't work, your brush is broken and needs to be repaired. Either using the vertex-tool, or deleting the brush and recreating it.
See also:
Reference: Finding the location of errors
The affected object may not work and/or cause general errors
Description:
See Texture axis perpendicular to face
The affected object may not work and/or cause general errors
Description:
Your map is too big (you have brush(es) too near to the edge of the grid) or you have invalid brushes. In 99.9999% of the cases, the cause is an invalid brush.
Solution:
If the problem-checker in Hammer (alt+p) doesn't find any offending brush(es), and you can't see brushes near the edge of the grid, check suspicious or recently vertex-edited brushes first. If you still can't find anything, you should use the cordon tools or visgroups to find them.
See also:
Reference: Finding the unfindable
Reference: Invalid solids
Description:
You have used a texture on a displacement that automatically creates prop_details (like grass/bushes) on its surface, and when you get this error there are simply too much of these made.
Solution:
Either reduce the size of the used surface or reduce the number of projected prop_details in the texture-properties ( in the texture that you used most to show these detail props). You can change this in the vmt of the texture(You should decrease the 'density'-value of the props emitted on the texture you used).
See also:
WIKI: Detail props
Description:
You have too many dynamic
