I have researched this across google for several hours and coming to a dead end. These excel files some of them you can open and re-save and some you cannot. They have the same permissions (security permissions) on the file and folders. If you create a new excel file and save it, it will save. If you reopen it then make any new changes it will come back with a sharing violation error. If you open an existing excel and make changes you get the same error.

Things I have tried so far.

1) Scanned the system for any malware, spyware, viruses: Clean
2) Turned off mcafee from the workstation and server
3) Shared folders and open files can be viewed from the computer management mmc snap in and this file is not being viewed or opened by another user.
4) Gave the user full administrative access to the directory tree and folder
5) Turned off Indexing
6) Updated the workstation with all the latest windows patches, updates and SP3
7) Disabled all uneccessary start up items and services
8) Logged in as the administrator and got the same error so its not a DACL issue

Thoughts??