I have a very similar problem as described here.
I also upgraded a mixed solution of C++/CLI and C# projects from Visual Studio 2008 to Visual Studio 2010. And now in Visual Studio 2010 one C++/CLI project always runs out of date.
Even if it has been compiled and linked just before and F5 is hit, the messagebox "The project is out of date. Would you like to build it?" appears. This is very annoying because the DLL file is very low-tiered and forces almost all projects of the solution to rebuild.
My pdb settings are set to the default value (suggested solution of this problem).
Is it possible the get the reason why Visual Studio 2010 forces a rebuild or thinks a project is up to date?
Any other ideas why Visual Studio 2010 behaves like that?
For Visual Studio/Express 2010 only. See other (easier) answers for VS2012, VS2013, etc
To find the missing file(s), use info from the article Enable C++ project system logging to enable debug logging in Visual Studio and let it just tell you what's causing the rebuild:
Open the devenv.exe.config file (found in %ProgramFiles%\Microsoft Visual Studio 10.0\Common7\IDE\ or in %ProgramFiles(x86)%\Microsoft Visual Studio 10.0\Common7\IDE\). For Express versions the config file is named V*Express.exe.config.
Add the following after the </configSections> line:
<system.diagnostics>
<switches>
<add name="CPS" value="4" />
</switches>
</system.diagnostics>
Restart Visual Studio
Open up DbgView and make sure it's capturing debug output
Try to debug (hit F5 in Visual Studio)
Search the debug log for any lines of the form:
devenv.exe Information: 0 : Project 'Bla\Bla\Dummy.vcxproj' not up to date because build input 'Bla\Bla\SomeFile.h' is missing.
(I just hit Ctrl+F and searched for not up to date) These will be the references causing the project to be perpetually "out of date".
To correct this, either remove any references to the missing files from your project, or update the references to indicate their actual locations.
Note: If using 2012 or later then the snippet should be:
<system.diagnostics>
<switches>
<add name="CPS" value="Verbose" />
</switches>
</system.diagnostics>
In Visual Studio 2012 I was able to achieve the same result easier than in the accepted solution.
I changed the option in menu Tools → Options → Projects and Solutions → Build and Run → *MSBuild project build output verbosity" from Minimal to Diagnostic.
Then in the build output I found the same lines by searching for "not up to date":
Project 'blabla' is not up to date. Project item 'c:\foo\bar.xml' has 'Copy to Output Directory' attribute set to 'Copy always'.
This happened to me today. I was able to track down the cause: The project included a header file which no longer existed on disk.
Removing the file from the project solved the problem.
We also ran into this issue and found out how to resolve it.
The issue was as stated above "The file no longer exists on the disk."
This is not quite correct. The file does exist on the disk, but the .VCPROJ file is referencing the file somewhere else.
You can 'discover' this by going to the "include file view" and clicking on each include file in turn until you find the one that Visual Studio can not find. You then ADD that file (as an existing item) and delete the reference that can not be found and everything is OK.
A valid question is: How can Visual Studio even build if it does not know where the include files are?
We think the .vcproj file has some relative path to the offending file somewhere that it does not show in the Visual Studio GUI, and this accounts for why the project will actually build even though the tree-view of the includes is incorrect.
The accepted answer helped me on the right path to figuring out how to solve this problem for the screwed up project I had to start working with. However, I had to deal with a very large number of bad include headers. With the verbose debug output, removing one caused the IDE to freeze for 30 seconds while outputting debug spew, which made the process go very slowly.
I got impatient and wrote a quick-and-dirty Python script to check the (Visual Studio 2010) project files for me and output all the missing files at once, along with the filters they're located in. You can find it as a Gist here: https://gist.github.com/antiuniverse/3825678 (or this fork that supports relative paths)
Example:
D:\...> check_inc.py sdk/src/game/client/swarm_sdk_client.vcxproj
[Header Files]:
fx_cs_blood.h (cstrike\fx_cs_blood.h)
hud_radar.h (cstrike\hud_radar.h)
[Game Shared Header Files]:
basecsgrenade_projectile.h (..\shared\cstrike\basecsgrenade_projectile.h)
fx_cs_shared.h (..\shared\cstrike\fx_cs_shared.h)
weapon_flashbang.h (..\shared\cstrike\weapon_flashbang.h)
weapon_hegrenade.h (..\shared\cstrike\weapon_hegrenade.h)
weapon_ifmsteadycam.h (..\shared\weapon_ifmsteadycam.h)
[Source Files\Swarm\GameUI - Embedded\Base GameUI\Headers]:
basepaenl.h (swarm\gameui\basepaenl.h)
...
Source code:
#!/c/Python32/python.exe
import sys
import os
import os.path
import xml.etree.ElementTree as ET
ns = '{http://schemas.microsoft.com/developer/msbuild/2003}'
#Works with relative path also
projectFileName = sys.argv[1]
if not os.path.isabs(projectFileName):
projectFileName = os.path.join(os.getcwd(), projectFileName)
filterTree = ET.parse(projectFileName+".filters")
filterRoot = filterTree.getroot()
filterDict = dict()
missingDict = dict()
for inc in filterRoot.iter(ns+'ClInclude'):
incFileRel = inc.get('Include')
incFilter = inc.find(ns+'Filter')
if incFileRel != None and incFilter != None:
filterDict[incFileRel] = incFilter.text
if incFilter.text not in missingDict:
missingDict[incFilter.text] = []
projTree = ET.parse(projectFileName)
projRoot = projTree.getroot()
for inc in projRoot.iter(ns+'ClInclude'):
incFileRel = inc.get('Include')
if incFileRel != None:
incFile = os.path.abspath(os.path.join(os.path.dirname(projectFileName), incFileRel))
if not os.path.exists(incFile):
missingDict[filterDict[incFileRel]].append(incFileRel)
for (missingGroup, missingList) in missingDict.items():
if len(missingList) > 0:
print("["+missingGroup+"]:")
for missing in missingList:
print(" " + os.path.basename(missing) + " (" + missing + ")")
I've deleted a cpp and some header files from the solution (and from the disk) but still had the problem.
Thing is, every file the compiler uses goes in a *.tlog file in your temp directory.
When you remove a file, this *.tlog file is not updated. That's the file used by incremental builds to check if your project is up to date.
Either edit this .tlog file manually or clean your project and rebuild.
I had a similar problem, but in my case there were no files missing, there was an error in how the pdb output file was defined: I forgot the suffix .pdb (I found out with the debug logging trick).
To solve the problem I changed, in the vxproj file, the following line:
<ProgramDataBaseFileName>MyName</ProgramDataBaseFileName>
to
<ProgramDataBaseFileName>MyName.pdb</ProgramDataBaseFileName>
I had this problem in VS2013 (Update 5) and there can be two reasons for that, both of which you can find by enabling "Detailed" build output under "Tools"->"Projects and Solutions"->"Build and Run".
"Forcing recompile of all source files due to missing PDB "..."
This happens when you disable debug information output in your compiler options (Under Project settings: „C/C++“->“Debug Information Format“ to „None“ and „Linker“->“Generate Debug Info“ to „No“: ). If you have left „C/C++“->“Program Database File Name“ at the default (which is „$(IntDir)vc$(PlatformToolsetVersion).pdb“), VS will not find the file due to a bug (https://connect.microsoft.com/VisualStudio/feedback/details/833494/project-with-debug-information-disabled-always-rebuilds).
To fix it, simply clear the file name to "" (empty field).
"Forcing rebuild of all source files due to a change in the command line since the last build."
This seems to be a known VS bug too (https://connect.microsoft.com/VisualStudio/feedback/details/833943/forcing-rebuild-of-all-source-files-due-to-a-change-in-the-command-line-since-the-last-build) and seems to be fixed in newer versions (but not VS2013). I known of no workaround, but if you do, by all means, post it here.
I don't know if anyone else has this same problem, but my project's properties had "Configuration Properties" -> C/C++ -> "Debug Information Format" set to "None", and when I switched it back to the default "Program Database (/Zi)", that stopped the project from recompiling every time.
Another simple solution referenced by Visual Studio Forum.
Changing configuration: menu Tools → Options → Projects and Solutions → VC++ Project Settings → Solution Explorer Mode to Show all files.
Then you can see all files in Solution Explorer.
Find the files marked by the yellow icon and remove them from the project.
It's OK.
Visual Studio 2013 -- "Forcing recompile of all source files due to missing PDB". I turned on detailed build output to locate the issue: I enabled "Detailed" build output under "Tools" → "Projects and Solutions" → "Build and Run".
I had several projects, all C++, I set the option for under project settings: (C/C++ → Debug Information Format) to Program Database (/Zi) for the problem project. However, this did not stop the problem for that project. The problem came from one of the other C++ projects in the solution.
I set all C++ projects to "Program Database (/Zi)". This fixed the problem.
Again, the project reporting the problem was not the problem project. Try setting all projects to "Program Database (/Zi)" to fix the problem.
I met this problem today, however it was a bit different. I had a CUDA DLL project in my solution. Compiling in a clean solution was OK, but otherwise it failed and the compiler always treated the CUDA DLL project as not up to date.
I tried the solution from this post.
But there is no missing header file in my solution. Then I found out the reason in my case.
I have changed the project's Intermediate Directory before, although it didn't cause trouble. And now when I changed the CUDA DLL Project's Intermediate Directory back to $(Configuration)\, everything works right again.
I guess there is some minor problem between CUDA Build Customization and non-default Intermediate Directory.
I had similar problem and followed the above instructions (the accepted answer) to locate the missing files, but not without scratching my head. Here is my summary of what I did. To be accurate these are not missing files since they are not required by the project to build (at least in my case), but they are references to files that don't exist on disk which are not really required.
Here is my story:
Under Windows 7 the file is located at %ProgramFiles(x86)%\Microsoft Visual Studio 10.0\Common7\IDE\%. There are two similar files devenv.exe.config.config and devenv.exe.config. You want to change later one.
Under Windows 7, you don't have permission to edit this file being in program files. Just copy it somewhere else (desktop) change it and than copy it back to the program files location.
I was trying to figure out how to connect DebugView to the IDE to see the missing files. Well, you don't have to do anything. Just run it, and it will capture all the messages. Make sure Capture Events menu option is selected in Capture menu which by default should be selected.
DebugView will NOT display all the missing files at once (at least it didn't for me)! You would have DebugView running and than run the project in Visual Studio 2010. It will prompt the project out of date message, select Yes to build and DebugView will show the first file that is missing or causing the rebuild. Open the project file (not solution file) in Notepad and search for that file and delete it. You are better off closing your project and reopening it again while doing this delete. Repeat this process until DebugView no longer shows any files missing.
It's kind of helpful to set the message filter to not up to date from the DebugView toolbar button or Edit → Filter/Highlight option. That way the only messages it displays are the one that has `not up to date' string in it.
I had lots of files that were unnecessary references and removing them all fixed the issue following the above steps.
Second way to find all the missing files at once
There is a second way to find these files all at once, but it involves (a) source control and (b) integration of it with Visual Studio 2010. Using Visual Studio 2010, add your project to a desired location or dummy location in source control. It will try to add all the files, including those that don't exist on disk as well but referenced in the project file. Go to your source control software like Perforce, and it should mark these files which don't exist on disk in a different color scheme. Perforce shows them with a black lock on them. These are your missing references. Now you have a list of them all, and you can delete all of them from your project file using Notepad and your project would not complain about being out of date.
For me it was the presence of a non-existing header file on "Header Files" inside the project. After removing this entry (right-click > Exclude from Project) first time recompiled, then directly
========== Build: 0 succeeded, 0 failed, 5 up-to-date, 0 skipped ==========
and no attempt of rebuilding without modification was done. I think is a check-before-build implemented by VS2010 (not sure if documented, could be) which triggers the "AlwaysCreate" flag.
If you are using the command-line MSBuild command (not the Visual Studio IDE), for example if you are targetting AppVeyor or you just prefer the command line, you can add this option to your MSBuild command line:
/fileLoggerParameters:LogFile=MyLog.log;Append;Verbosity=diagnostic;Encoding=UTF-8
As documented here (warning: usual MSDN verbosity). When the build finishes, search for the string will be compiled in the log file created during the build, MyLog.log.
I'm using Visual Studio 2013 Professional with Update 4 but didn't find resolution with any of the other suggestions, however, I did manage to resolve the issue for my Team project.
Here's what I did to cause the problem -
Created a new class object (Project -> Add Class)
Renamed the file via Solution Explorer and clicked yes when asked if I wanted to automatically rename all references to match
Here's what I did to solve the problem -
Go to Team Explorer Home
Click Source Control Explorer
Drill into the folder where all of the class/project files are
Found the ORIGINAL filename in the list and deleted it via right-click
Build
If this is the case for you then just be extra sure that you're deleting the phantom file rather than the actual one you want to keep in the project.
I had this problem and found this:
http://curlybrace.blogspot.com/2005/11/visual-c-project-continually-out-of.html
Visual C++ Project continually out-of-date (winwlm.h macwin32.h rpcerr.h macname1.h missing)
Problem:
In Visual C++ .Net 2003, one of my projects always claimed to be out of date, even though nothing had changed and no errors had been reported in the last build.
Opening the BuildLog.htm file for the corresponding project showed a list of PRJ0041 errors for these files, none of which appear on my system anywhere:
winwlm.h macwin32.h rpcerr.h macname1.h
Each error looks something like this:
MyApplication : warning PRJ0041 : Cannot find missing dependency 'macwin32.h' for file 'MyApplication.rc'.
Your project may still build, but may continue to appear out of date until this file is found.
Solution:
Include afxres.h instead of resource.h inside the project's .rc file.
The project's .rc file contained "#include resource.h". Since the resource compiler does not honor preprocessor #ifdef blocks, it will tear through and try to find include files it should be ignoring. Windows.h contains many such blocks. Including afxres.h instead fixed the PRJ0041 warnings and eliminated the "Project is out-of-date" error dialog.
In my case one of the projects contains multiple IDL files. The MIDL compiler generates a DLL data file called 'dlldata.c' for each of them, regardless of the IDL file name. This caused Visual Studio to compile the IDL files on every build, even without changes to any of the IDL files.
The workaround is to configure a unique output file for each IDL file (the MIDL compiler always generates such a file, even if the /dlldata switch is omitted):
Right-click the IDL file
Select Properties - MIDL - Output
Enter a unique file name for the DllData File property
I spent many hours spent tearing out my hair over this. The build output wasn't consistent; different projects would be "not up to date" for different reasons from one build to the next consecutive build.
I eventually found that the culprit was DropBox (3.0.4). I junction my source folder from ...\DropBox into my projects folder (not sure if this is the reason), but DropBox somehow "touches" files during a build. Paused syncing and everything is consistently up-to-date.
There are quite a few potential reasons and - as noted - you need to first diagnose them by setting MSBuild verbosity to 'Diagnostic'. Most of the time the stated reason would be self explanatory and you'd be able to act on it immediatelly, BUT occasionally MSBuild would erroneously claim that some files are modified and need to be copied.
If that is the case, you'd need to either disable NTFS tunneling or duplicate your output folder to a new location. Here it is in more words.
This happened to me multiple times and then went away, before I could figure out why. In my case it was:
Wrong system time in the dual boot setup!
Turns out, my dual boot with Ubuntu was the root cause!! I've been too lazy to fix up Ubuntu to stop messing with my hardware clock. When I log into Ubuntu, the time jumps 5 hours forward.
Out of bad luck, I built the project once, with the wrong system time, then corrected the time. As a result, all the build files had wrong timestamps, and VS would think they are all out of date and would rebuild the project.
Most build systems use data time stamps to determine when rebuilds should happen - the date/time stamp of any output files is checked against the last modified time of the dependencies - if any of the dependencies are fresher, then the target is rebuilt.
This can cause problems if any of the dependencies somehow get an invalid data time stamp as it's difficult for the time stamp of any build output to ever exceed the timestamp of a file supposedly created in the future :P
For me, the problem arose in a WPF project where some files had their 'Build Action' property set to 'Resource' and their 'Copy to Output Directory' set to 'Copy if newer'. The solution seemed to be to change the 'Copy to Output Directory' property to 'Do not copy'.
msbuild knows not to copy 'Resource' files to the output - but still triggers a build if they're not there. Maybe that could be considered a bug?
It's hugely helpful with the answers here hinting how to get msbuild to spill the beans on why it keeps building everything!
If you change the Debugging Command arguments for the project, this will also trigger the project needs to be rebuilt message. Even though the target itself is not affected by the Debugging arguments, the project properties have changed. If you do rebuild though, the message should disappear.
I had a similar issue with Visual Studio 2005, and my solution consisted of five projects in the following dependency (first built at top):
Video_Codec depends on nothing
Generic_Graphics depends on Video_Codec
SpecificAPI_Graphics depends on Generic_Graphics
Engine depends on Specific_Graphics
Application depends on Engine.
I was finding that the Video_Codec project wanted a full build even after a full clean then rebuild of the solution.
I fixed this by ensuring the pdb output file of both the C/C++ and linker matched the location used by the other working projects. I also switched RTTI on.
Another one on Visual Studio 2015 SP3, but I have encountered a similar issue on Visual Studio 2013 a few years back.
My issue was that somehow a wrong cpp file was used for precompiled headers (so I had two cpp files that created the precompiled headers). Now why did Visual Studio change the flags on the wrong cpp to 'create precompiled headers' without my request I have no clue, but it did happen... maybe some plugin or something???
Anyway, the wrong cpp file includes the version.h file which is changed on every build. So Visual Studio rebuilds all headers and because of that the whole project.
Well, now it's back to normal behavior.
I had a VC++ project that was always compiling all files and had been previously upgraded from VS2005 to VS2010 (by other people). I found that all cpp files in the project except StdAfx.cpp were set to Create (/Yc) the precompiled header. I changed this so that only StdAfx.cpp was set to create the precompiled header and the rest were set to Use (/Yu) the precompiled header and this fixed the problem for me.
I'm on Visual Studio 2013 and just updated to the Windows 10 May 2019 update and compiling suddenly had to be redone every time, regardless of changes. Tried renaming the pch to ProjectName instead of TargetName, looked for missing files with the detailed log and that Python script, but in the end it was my time was not synced with MS's servers (by like milliseconds).
What resolved this for me was
"Adjust date and time" in the control panel
"Sync Now"
Now my projects don't need to be recompiled for no reason.
I think that you placed some newline or other whitespace. Remove it and press F5 again.
The .NET projects are always recompiled regardless. Part of this is to keep the IDE up to date (such as IntelliSense). I remember asking this question on an Microsoft forum years ago, and this was the answer I was given.
I have a C# project which includes one exe and 11 library files. The exe references all the libraries, and lib1 may reference lib2, lib3, lib4, etc.
If I make a change to a class in lib1 and built the solution, I assumed that only lib1 and the exe would need to be changed. However, all dll's and the exe are being built if I want to run the solution.
Is there a way that I can stop the dependencies from being built if they have not been changed?
Is the key this phrase? "However, all dll's and the exe are being built if I want to run the solution"
Visual Studio will always try to build everything when you run a single project, even if that project doesn't depend on everything. This choice can be changed, however. Go to Tools|Options|Projects and Solutions|Build and Run and check the box "Only build startup projects and dependencies on Run". Then when you hit F5, VS will only build your startup project and the DLLs it depends on.
I just "fixed" the same problem with my VS project. Visual Studio did always a rebuild, even if didn't change anything. My Solution: One cs-File had a future timestamp (Year 2015, this was my fault). I opened the file, saved it and my problem was solved!!!
I am not sure if there is a way to avoid dependencies from being built. You can find some info here like setting copylocal to false and putting the dlls in a common directory.
Optimizing Visual Studio solution build - where to put DLL files?
We had a similar problem at work. In post-build events we were manually embedding manifests into the outputs in the bin directory. Visual Studio was copying project references from the obj dir (which weren't modified). The timestamp difference triggered unnecessary rebuilds.
If your post-build events modify project outputs then either modify the outputs in the bin and obj dir OR copy the modified outputs in the bin dir on top of those in the obj dir.
You can uncheck the build option for specified projects in your Solution configuration:
(source: microsoft.com)
You can can create your own solution configurations to build specific project configurations...
(source: microsoft.com)
We actually had this problem on my current project, in our scenario even running unit tests (without any code changes) was causing a recompile. Check your build configuration's "Platform".
If you are using "Any CPU" then for some reason it rebuilds all projects regardless of changes. Try using processor specific builds, i.e. x86 or x64 (use the platform which is specific to the machine architecture of your machine). Worked for us for x86 builds.
(source: episerver.com)
Now, after I say this, some propeller-head is going to come along and contradict me, but there is no way to do what you want to do from Visual Studio. There is a way of doing it outside of VS, but first, I have a question:
Why on earth would you want to do this? Maybe you're trying to save CPU cycles, or save compile time, but if you do what you're suggesting you will suddenly find yourself in a marvelous position to shoot yourself in the foot. If you have a library 1 that depends upon library 2, and only library 2 changes, you may think you're OK to only build the changed library, but one of these days you are going to make a change to library 2 that will break library 1, and without a build of library 2 you will not catch it in the compilation. So in my humble opinion, DON'T DO IT.
The reason this won't work in VS2005 and 2008 is because VS uses MSBuild. MSBuild runs against project files, and it will examine the project's references and build all referenced projects first, if their source has changed, before building the target project. You can test this yourself by running MSBuild from the command line against one project that has not changed but with a referenced project that has changed. Example:
msbuild ClassLibrary4.csproj
where ClassLibrary4 has not changed, but it references ClassLibrary5, which has changed. MSBuild will build lib 5 first, before it builds 4, even though you didn't mention 5.
The only way to get around all these failsafes is to use the compiler directly instead of going through MSBuild. Ugly, ugly, but that's it. You will basically be reduced to re-implementing MSBuild in some form in order to do what you want to do.
It isn't worth it.
Check out the following site for more detailed information on when a project is built as well as the differences between build and rebuild.
I had this problem too, and noticed these warning messages when building on Windows 7 x64, VS2008 SP1:
cl : Command line warning D9038 : /ZI is not supported on this platform; enabling /Zi instead
cl : Command line warning D9007 : '/Gm' requires '/Zi'; option ignored
I changed my project properties to:
C/C++ -> General -> Debug Information Format = /Zi
C/C++ -> Code Generation -> Enable Minimal Build = No
After rebuilding I switched them both back and dependencies work fine again. But prior to that no amount of cleaning, rebuilding, or completely deleting the output directory would fix it.
I don't think there's away for you to do it out of the box in VS. You need this add-in
http://workspacewhiz.com/
It's not free but you can evaluate it before you buy.
Yes, exclude the non-changing bits from the solution. I say this with a caveat, as you can compile in a way where a change in build number for the changed lib can cause the non built pieces to break. This should not be the case, as long as you do not break interface, but it is quite common because most devs do not understand interface in the .NET world. It comes from not having to write IDL. :-)
As for X projcts in a solution, NO, you can't stop them from building, as the system sees a dependency has changed.
BTW, you should look at your project and figure out why your UI project (assume it is UI) references the same library as everything else. A good Dependency Model will show the class(es) that should be broken out as data objects or domain objects (I have made an assumption that the common dependency is some sort of data object or domain object, of course, but that is quite common). If the common dependency is not a domain/data object, then I would rethink my architecture in most cases. In general, you should be able to create a path from UI to data without common dependencies other than non-behavioral objects.
Not sure of an awesome way to handle this, but in the past if I had a project or two that kept getting rebuilt, and assuming I wouldn't be working in them, I would turn the build process off for them.
Right click on the sln, select configuration manager and uncheck the check boxes. Not perfect, but works when Visual Studio isn't behaving.
If you continue to experience this problem, it may be due to a missing or out of date calculated dependency (like a header) that is listed in your project, but does not exist.
This happens to me especially common after migrating to a new version (for example: from 2012 to 2013) because VS may have recalculated dependencies in the conversion, or you are migrating to a new location.
A quick check is to double-click every file in offending project from solution explorer. If you discover a file does not exist, that is your problem.
Failing a simple missing file: You may have a more complicated build date relationship between source and target. You can use a utility to find out what front-end test is triggering the build. To get that information you can enable verbose CPS logging. See: Andrew Arnott - Enable C++ and Javascript project system tracing (http://blogs.msdn.com/b/vsproject/archive/2009/07/21/enable-c-project-system-logging.aspx). I use the DebugView option. Invaluable tool when you need it.
(this is a C# specific question, but a different post was merged as identical)
I've got a solution containing multiple projects. I'm only changing the code in one of them, but every time I hit Ctrl+Shift+B, Visual Studio rebuilds all of the others.
I want it to build the other projects, so this is good. What's not good is that, normally, it would see that there was nothing to do. I have a wonky dependency somewhere, so this isn't working.
Is there a tool or macro (or switch) that'll explore the dependency tree and tell me which files are missing or out-of-date, so that I can get it to stop?
I know that I can solve this specific case, by (e.g.) touching all of the project files.
Unfortunately, I've often seen this situation when a file is configured to produce an output file (e.g. an IDL file is configured to output a typelibrary, but doesn't contain a 'library' block, so it'll never create a TLB).
This wouldn't be resolved by touching all of the project files, so I'm looking for something more general to add to my personal toolbox that'll easily tell me why a file is being rebuilt, whether it be because it's older than a dependency, or because the project is misconfigured to expect an output file that will never be produced.
In Options / Projects and Solutions / Build and Run turn up the MSBuild project build output verbosity to Detailed. It should give you an idea of why it is rebuilding all the projects.
If I understand you right, you might solve this by touching all your project's files. It may be caused by a source-file having a last-modified-time that's in the future.
Edit:
I know that I can solve this specific case, by (e.g.) touching all of the project files, but I'd like to add something to my personal box of tricks that I can use in the future, in the general case.
I'm confused - what's the 'general case' of this problem?
Not that I've found. If you know that a project is not going to change often, you can tell the Configuration Manager not to build it. (Right-click on the Solution, and select Configuration Management)
As far as I know ctrl + shift + b is by default bound to BuildSolution, so that would be why all your projects are being build. i'm not really sure what else you could use except for rightclicking the project and pressing build :)
You might want to check in Tools>Option>Projects and Solutions and check if your option is set to Only Build startup project and dependencies instead of all the solution.
Or instead of using ctrl+shirt+b you should simply press F6 on the project you want to build :)
You can use shift+F6 to build just the current project.
While not directly answering my question: "is there a tool that'll work this out for me?", I found the specific problem by using SysInternals Process Monitor:
The project was configured with /analyze, which requires Visual Studio Team Edition, but the version on this PC is Visual Studio Professional, which doesn't support it. Unfortunately, there appears to be a bug in Visual Studio, where it thinks that the .pchast file should be created, even though it has no way to do so. I've raised this on Connect.
I think I might write a macro for Visual Studio Professional that, if /analyze is turned on, simply creates an empty .pchast file at the end of the build...