Sometimes to correct the condition you have to reboot the computer, and it may persist even after a reboot. The error message isn't very helpful, since it doesn't tell you which person or program has a lock on the file!
A new freeware utility called Unlocker helps get around this problem. When installed, it creates a right-click context menu in Explorer that provides a list of which processes are holding a lock on a particular file. Select the processes, click Unlock, and the locks are freed up. You're now free to move, delete or modify the file.
Unlocker differs from other utilities because it works by closing handles held for a particular file by a process. Other utilities only kill the host process that has a lock on a file -- and if the host process in question is Explorer or some other program that really should be left running, this isn't practical.
Unlocker can also unlock all locks on a particular drive or in a particular folder. Note: Use this function with extreme caution! (It would be bad to do this on your system drive, for instance). Mapped network drives are also supported.
For the most part, Unlocker works only with ordinary non-system files, such as documents. DLLs are not tracked through Unlocker, which is for the best since DLL associations with parent executables should not be tampered with in this fashion for the sake of system stability.
The top 10 tips of 2005
Tip #1: How to change the Windows XP Product Activation Key Code
Tip #2: Create a bootable USB flash drive -- in a flash!
Tip #3: Create a bootable Windows Server 2003 CD
Tip #4: 8 common causes for 'delayed write failed' errors
Tip #5: Ultimate boot CD packs in recovery, repair utilities
Tip #6: Install Windows Server 2003 silently
Tip #7: Uninstall 'stubborn' programs
Tip #8: What to do when your hard drive fails
Tip #9: Windows XP and Windows Server 2003 volume shadow copy service
Tip #10: 'Unlocker' reveals processes that lock files
Serdar Yegulalp wrote for Windows Magazine from 1994 through 2001, covering a wide range of technology topics. He now uses his expertise in Windows NT, Windows 2000 and Windows XP as publisher of The Windows 2000 Power Users Newsletter and writes technology columns for TechTarget.
This was first published in May 2005