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.

1. Simply right click the folder or file and select Unlocker

2. If the folder or file is locked, a window listing of lockers will appear

3. Simply click Unlock All and you are done!

Of course I only compare here the unlocking features. Process Explorer and Take Control are very good programs featuring much more things than just unlocking folders. The goal of this list is not really to pretend Unlocker is better but instead to provide a list of all other alternative programs in case you have some difficulties with Unlocker.