If you are admin on the server sharing the file over the network, you can use the Windows in-built feature:
- Start → My Computer → Right-click → Manage gets you to the Computer
Management console - In the left nav, navigate to Systems Tools → Shared Folders
- You can view Shares, Sessions & Open Files here. This allows you to find out who has opened which files from which workstations.
- Right-click on an item in the list to be able to remove the file lock.
Hope this helps.