If you’ve recently upgraded to SP1 and tried to build a solution checked out from TFS you might have come across the following dialog. Not only does it not allow you to cancel the build process, but it also REPEATEDLY THROWS THE DIALOG PREVENTING YOU FROM STOPPING THE PROCESS. Very annoying.

There is a hotfix available via connect and code gallery that will stop this problem.
Connect Bug Entry:
http://connect.microsoft.com/VisualStudio/feedback/details/650587/vs-2010-sp1-changes-packagecode-in-vdproj-on-each-build-but-fails-as-source-controlled
Hotfix download:
http://connect.microsoft.com/VisualStudio/Downloads/DownloadDetails.aspx?DownloadID=35848
http://archive.msdn.microsoft.com/KB2529927