File is used by another process. How to know which process?

Question

I keep getting that exception in my program. How do I know which process locked it, either by program code or by doing something with windows?

System.IO.IOException : The process cannot access the file 'file.ext' because it is being used by another process.

Answer 1

Have a look at this: http://ccollomb.free.fr/unlocker/

I use it all the time, tells you which process has locked it and gives you the chance to unlock it fully. Useful especially for when your debugging image manipulation apps and it bombs out without closing the file properly.

Hope this helps!

Sean

Answer 2

You can use a tool like ProcessMon to see what process is locking a file.

Answer 3

You can use ProcessExplorer to search for the file:

• http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx

Just run that, hit Ctrl-F and type in the name of the file which is locked - it will find all open handles which match the given name, and tell you which process it belongs to.