If you have a user reporting the error message stating that file is locked by the wrong user in excel, that's because there may be a corrupted temp file for excel. Please do the following to solve this issue.
- Open the folder where the Document is located.
- Click Tools=>Folder Options
- Click the View tab
- Scoll down to Advanced Settings>Hidden files and folders
- Select Show hidden files and folders and Unselect Hide protected operating system files
-
Look for a temp lock file and delete it. It should look something like ~$filename.xlsx or whatever file extension the it was saved in.
(In my case, this file had become corrupt and was stuck displaying an earlier modify date from a few days ago..)