Windows 7: File In Use when deleting file
Sometimes I can't delete a file because it's being used by some unknown applications. How can I find out what apps?
Unlocker is a great tool for this.
Make sure you download the 64-bit version if yiu have a 64-bit OS.
I use SysInternals' Process Explorer. Search for the locked file. Not only will PE tell you which application locked it, but also what thread in that application opened it. In certain cases (only recommended if you know what you're doing!) you can get away by killing one thread, rather than an entire application.
At any rate, it will tell you who locked the file.