Whenever you install a service pack on a Windows machine, it’s not unusual for it to leave plenty of files strewn about your system disk in its wake. What’s unusual about Windows Vista SP1, however, is that it includes its own clean-up utility.

If you run it after performing an SP1 install it can recover somewhere between 1.2 and 2.0 GB of disk space from your hard disk. That’s the upside. If you elect to use this utility, however, the SP1 install becomes irreversible (unless you can restore a backup that includes those missing files) and you can’t roll back if you want or need to. That’s the downside.

Because I now make daily backups, the prospect of losing those files didn’t scare me too much. I went ahead and ran it, and have yet to experience any ill effects as a result. Here’s how to use this utility:

1. Open a command window inside Vista (I usually just type cmd into the search box in the Vista Start menu to do this).
2. Type the program name for the SP1 cleanup utility: vsp1cln.exe.
3. Wait for the utility to complete.

Here’s a screen dump of what you’ll see as that process completes, rendered in plain text for easy readability: