Recently my customer encounters the following errors in TFS 2005: Exception Message: The process cannot access the file 'X:\Program Files\Microsoft Visual Studio 2005 Team Foundation Server\Web Services\VersionControl\App... because it is being used by another process. (type IOException) Finally, we found that it is because that TFS application pool in IIS is configured to use multiple worker processes. Please configure it back to 1 to solve this problem...