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Windows.old is a collection of files preserved from a previous Windows installation when you upgrade. I'll look at how best to deal with Windows.old.

I went from XP to Vista. Every time that I run a scan it spends 10 min. running through windows.old. How do I delete windows.old?

When you upgrade Windows without performing a format during the install, Windows setup will keep files that were part of the old Windows installation in a folder named, surprisingly enough, 'windows.old'.

Yes, you can delete it.

But, you want to make sure that you're ready to before you do so.


Windows.old, as described by Microsoft:

... files that were used in your previous version of Windows are stored in the Windows.old folder. The type of files in this folder depends on your computer.

Fairly vague, but understandably so. It really does depend on how your computer was setup and how you used it.

"Yes, we can remove it, but to be safe we really should save a backup copy first."

While I typically don't use Windows.old myself (I prefer clean installs over the upgrades that cause Windows.old to be created), I'm lead to believe that it contains copies of the following folders from the previous installation:

  • Documents and Settings

  • Program Files

  • Windows

In other words it's saved a lot of information from your prior installation.

It can be useful, if you need to recover something from it.

However, it can take up a lot of space.

Yes, we can remove it, but to be safe we really should save a backup copy first.

Backing Up Windows.old

I'll be clear: you can skip this step if you are absolutely positive there's nothing in Windows.old that you'll ever need. And 99% of it is almost certainly exactly that - stuff you'll never ever need.

That other 1% though, might make this step very worthwhile.

Using your backup program, make a specific and separate backup copy of the Windows.old folder and everything in it.

Or, burn it to DVD.

Or, copy it to another machine that has more room.

Or, use 7-zip or another archival program to bundle it into a single zip file that takes up less space, and leave it on your computer.

Whatever - the idea is that before you remove it you have a copy of it saved somewhere where you can get back to it, should you ever need to.

Deleting Windows.old

Windows.old is just a folder like any other folder. The only real significance it has is what it contains.

What that means is that you can delete it just like any other folder.

In Windows Explorer, right click on it, and click on Delete.

In a Windows Command Prompt enter "RD /s C:\Windows.old" and answer the confirming question.

That's all there really is to it.

Article C4670 - December 4, 2010 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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