Started up my Lenovo desktop PC running Win10 with AU installed and found it had put on a bit of weight overnight. 20-30gb in fact. Had a good look round thinking that that amount of gb's would be fairly easy to spot but nothing obvious shows up.
How many restore points do you have? Do you have a Windows.old folder? C cleaner tools - system restore - delete all but latest 2 . If you have a Windows.old folder check its size . You can use disk cleanup to delete it but check the procedure first.
Thanks for your reply John the problem is now solved.
I'd been having problems with the free version of EaseUS Todo recently which unknown to me had resulted in an overweight file. I'm now looking for a decent paid for back up which even I could follow.