One of the things that continually frustrates me about building Windows Mobile applications in Visual Studio is that for some reason it takes so long to do a build. Behind the scenes there is a lot that goes on and I always forget that there is one part of the build that you can mostly do without, the platform verification. As pointed out by the now quite old post by the Visual Studio for Devices team you can disable this part of the build quite easily:
1) Open the file %windir%\Microsoft.NET\Framework\v2.0.50727\Microsoft.CompactFramework.Common.Targets for editing.
2) Go to the line which reads:
and change it to:
Name="PlatformVerificationTask" Condition="'$(SkipPlatformVerification)' != 'true'">
3) Add the SkipPlatformVerification environment variable to the system and set it to "true" (To re-enable Platform Verification set the environment variable to "false")
4) Restart Visual Studio for the changes to take effect (If building from the command line using MSBuild, add /p:SkipPlatformVerification=true to your command line to turn off the task. You can specify the variable in the project file also, so that this information is persisted across sessions).
As noted by Thomas you may just want to disable this functionality, instead of having it contingent on an environment variable. In this case just change the PlatformVerificationTask line to:
Doing this you should notice that your mobile projects build just as fast as other projects within Visual Studio. Note: This is still relevant in Visual Studio 2008 with SP1.