This is the second time we have hit this error so this time it was a quick fix. But if you don’t know what it is you might be led astray by the message. When we have received this error is has nothing to do with permissions. This typically occurs on a build failure:

The real reason is found in the Event Viewer on the TFS Web Server in all these Errors:

If you scroll through the jumbled Web Request Details within the event details you will see:

Exception Message: There is not enough space on the disk.
 (type IOException)
Exception Stack Trace:    at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.FileStream.WriteCore(Byte[] buffer, Int32 offset, Int32 count)
   at Microsoft.TeamFoundation.Framework.Server.TeamFoundationFileService.InternalCopyTo(Stream source, Stream destination, Int32 bufferSize)
   at Microsoft.TeamFoundation.Framework.Server.TeamFoundationFileService.CopyStreamToTempStream(TeamFoundationRequestContext requestContext, Stream stream, Int64 compressedLength, CompressionType& compressionType, Boolean compressOutput, Boolean useFileStream)
   at Microsoft.TeamFoundation.Framework.Server.TeamFoundationFileService.RetrieveFile(TeamFoundationRequestContext requestContext, Int32 fileId, Boolean compressOutput, Byte[]& hashValue, Int64& contentLength, CompressionType& compressionType, String& fileName, Boolean failOnDeletedFile, Boolean returnNullIfDelta, Boolean forceFileStream, Boolean readIncompleteData)
   at Microsoft.TeamFoundation.Framework.Server.TeamFoundationFileService.RetrieveFile(TeamFoundationRequestContext requestContext, Int32 fileId, Boolean compressOutput, Byte[]& hashValue, Int64& contentLength, CompressionType& compressionType)
   at Microsoft.TeamFoundation.Server.Core.MidTierDownloadState.CacheMiss(FileCacheService fileCacheService, FileInformation fileInfo, Boolean compressOutput)
   at Microsoft.TeamFoundation.Server.Core.FileCacheService.RetrieveFileFromDatabase(TeamFoundationRequestContext requestContext, FileInformation fileInfo, IDownloadState downloadState, Boolean compressOutput, Stream databaseStream)
   at Microsoft.TeamFoundation.Server.Core.GenericDownloadHandler.DownloadFile(TeamFoundationRequestContext requestContext, DownloadContext downloadContext, HttpRequest request, HttpResponse response, HandleErrorDelegate errorDelegate)

The reason we ran out of disk space is due to IIS Logging. We were having giant transaction logs being recorded for all requests to the TFS Web Services. Archiving (deleting ) these restored our space quickly.