Find out which process is locking a file or folder in Windows

Find out which process is locking a file or folder in Windows

http://superuser.com/questions/117902/find-out-which-process-is-locking-a-file-or-folder-in-windows

Have a look at Process Explorer (procexp.exe).
From its introduction:

Ever wondered which program has a particular file or directory open? Now you can find out.

To find out what process is using a specific file follow these steps:

1. Go to Find, Find Handle or DLL.. or simply press Ctrl+F.
   
2. Enter the name of the file and press Search.
   
3. Process Explorer will list all processes that have a handle to the file open. Click on an entry to focus the process in the main window.
   
4. Optionally, you can then even close the handle manually through the lower pane (Ctrl+L):