Upgraded to Windows 7? Can you safely move Windows.old to another drive?

When you upgrade XP or Vista to Windows 7 with the Custom (Advanced) option, the installation program puts all of your data and settings into the C:Windows.old folder. That folder therefore has some very important stuff in it.

But no programs expect to find their files in Windows.old, so it does no harm to move the folder and its many subfolders elsewhere.

But not immediately. The first thing you should do with Windows.old is move your data out of it and back into Users where it belongs. See the third page of How to Upgrade to Windows 7 for details. Once you’ve moved those files out, there’s no harm in moving what’s left in Windows.old to an external hard drive, or even burn it to DVDs.