MSBuild & TeamBuild - BuildInParallel failing because of MSB3021 file permission violation

Question

I maintain the build of a fairly large piece of software, consisting of roughly 350 csharp projects. Our build time for a debug built clocks in at about 17 minutes.

I h

Answer 1

MS Build Copy task has undocumented feature, at least Google keeps silence. If set system wide environment variable MSBUILDALWAYSRETRY=1 This task will retry to copy a file even it gets Access Denied exception during copy operation

Example of output

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets (3513): Got System.UnauthorizedAccessException: Access to the path 'C:\Builds\8\28\Binaries\Release\fr\System.Spatial.resources.dll' is denied.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.File.InternalCopy(String sourceFileName, String destFileName, Boolean overwrite, Boolean checkHost)
   at System.IO.File.Copy(String sourceFileName, String destFileName, Boolean overwrite)
   at Microsoft.Build.Tasks.Copy.CopyFileWithLogging(FileState sourceFileState, FileState destinationFileState)
   at Microsoft.Build.Tasks.Copy.DoCopyWithRetries(FileState sourceFileState, FileState destinationFileState, CopyFileWithState copyFile) copying C:\Builds\8\28\Sources\Main\Solutions\packages\System.Spatial.5.2.0\lib
et40\fr\System.Spatial.resources.dll to C:\Builds\8\28\Binaries\Release\fr\System.Spatial.resources.dll and HR is -2147024891
 C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets (3513): Retrying on ERROR_ACCESS_DENIED because MSBUILDALWAYSRETRY = 1
 C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets (3513): Could not copy "C:\Builds\8\28\Sources\Main\Solutions\packages\System.Spatial.5.2.0\lib
et40\fr\System.Spatial.resources.dll" to "C:\Builds\8\28\Binaries\Release\fr\System.Spatial.resources.dll". Beginning retry 1 in 1000ms. Access to the path 'C:\Builds\8\28\Binaries\Release\fr\System.Spatial.resources.dll' is denied.