Ever had such an annoying message given by Windows?

It has many other flavors:
Cannot delete file: Access is denied
There has been a sharing violation.
The source or destination file may be in use.
The file is in use by another program or user.
Make sure the disk is not full or write-protected and that the file is not currently in use.
Unlocker is an Explorer extension that allows you with a simple right-click of the mouse on a file or folder to get rid of error message such as error deleting file or folder, cannot delete folder: it is used by another person or program.
Recommended software
I have been asked many times by family, friends, colleagues and recently Unlocker users which software I find to be the best. So here is software I recommend every user should use on their computer.
Link: Unlocker