If you ever have to use Process Monitor (formerly Process Explorer) to find out which process is holding onto a file that needs to be accessed, you can follow these steps:
- Download Process Monitor from here: http://technet.microsoft.com/en-us/sysinternals/bb896645.aspx
- Start capture (enabled by default, but can be toggled in the File menu)
- Click Filter
- In the dropdown menu, click Filter…
- Change the two dropdown menus to display Path, then Contains instead of the default
- In the text field to the right, write out all or part of the file path (e.g. C:\Windows\filename.exe)
- Click Add and then OK. The filter should now only display when that filepath is accessed.