Тут описано решение, которое мне помогло — http://codeclimber.net.nz/archive/2008/11/12/red-x-on-build-folder-on-team-explorer.aspx first of all you should to rename the cache folder for Team Foundation «C:\Documents and Settings\[accountname]\Local Settings\Application Data\Microsoft\Team Foundation\2.0″ (in Vista or Windows 2008 the path is “C:\Users\[accountname]\AppData\Local\Microsoft\Team Foundation\2.0\Cache”) Then execute this command line: Start > Run : “devenv /resetuserdata».