Yes, even my latest Windows 10 version 21H1 still uses the Windows 7 File History. You said System Image Backup can't find your external drive - is that correct ? Try turning File History on and see. Normally, when you connect your external drive you should have a drive letter F:, G: or something like that.Oh, you are using windows 7 backup and restore to create a system image backup. Well I have used that before and I might use it again but it is really annoying and when it failed to find a drive then I decided not to use it but you can't turn it off it just makes the computer think there is something wrong and gives you constant notifications and asks you to back up.