We have a strange problem since we use Client 2 IR2/3 and 4 now also.

Mostly it happends with Excel 2007 files! If a Win7 user (32bit) with IR4 client opens the file and then close just the Worksheet after a while, the file is still in use and locked. No others can open it and they get a already in use message. But If the user close the whole Excel application and not only the Worksheet, then the file is not locked anymore! Strange thing is, on serverside the file looks not as open. Office 2007 is fully patched and the File Caching and Commit are disabled on clientside and Oplock is disabled on serverside.

Any suggestions or same experiences?