I upgraded my son’s Dell laptop from Vista to Windows 7 recently. Did a custom install without reformatting the hard drive. Everything went fine but after installing some essential programs and putting his 20GB of music back from an external drive, I couldn’t reinstall his 20GB of photos as I was out of disk space. This Dell 1545 came with a 160GB hard drive which should have been way more than enough. What was hogging all the disk space?

I’m not a great lover of Windows Explorer so I downloaded the free Xinorbis to analyse the folder sizes on the hard drive. Straight away I could see that a folder called Windows.old was taking up 63GB of space! I googled windows.old and discovered that the Windows 7 installation had backed up the entire Vista set up here. I didn’t need anything from Windows.old as everything important was backed up to an external drive so I deleted the folder using great instructions I found here.

So if you’ve moved up from Vista to Windows 7 by doing a custom install and without reformatting the hard drive and were wondering what had happened to all your disk space, watch out for Windows.old.