When SP1 for Windows Vista updates or removes a file it backs up the old one encase the install fails or you want to uninstall SP1 at a later time.

This guide shows you how to run a Windows Vista service pack 1 disk clean-up. This will permanently remove the backed up files replaced or removed by Vista SP1.

Warning: Running the Vista SP1 disk clean-up tool permanently removes the ability to uninstall SP1. Use this tool at your own risk.

Vista SP1 Disk Clean-up

1. Click the Start orb, All Programs, Accessories, and click Command Prompt.
2. Type vsp1cln.exe and then press Enter on your keyboard.
3. Another command prompt box will open with a warning about running the SP1 disk clean-up tool.

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4. Type y to start the clean-up.
5. Wait a while and when it’s done the command prompt window will close.