If you use Windows' built-in option to reset your computer and erase data you might find that you have left behind a lot of personal data.

Reseting is normal when you flog an old PC but now Vole’s new update to the data wiping tools in Windows 10 and Windows 11 means that sensitive data is being left behind.

Microsoft MVP Rudy Ooms found that Windows 10 version 21H2 and Windows 11 version 21H2 found the data wiping function left behind user data in the Windows.old folder. Versions of the operating system prior to 21H2 did not suffer from this issue.

Ooms started off looking at the process of remotely wiping computers in various ways, and was surprised to find that in all of his tests using Windows 10 and Windows 11 version 21H2, data that users would rightly expect to be deleted in fact remained on the hard drive.

Ooms tweeted: “It is worth reiterating that while the main focus of the tests are on remote wiping, the same worrying results were found with local wipes.”

Ooms suggests that you double check the contents of your hard drive after performing a wipe, and manually delete the Windows.old folder if necessary. He has also produced a PowerShell script which can be used to ensure that a drive wipe really does erase all data, including the Windows.old folder.