Full 128GB Harddrive though only 31GB are findable. What to do?

My Windows 10 laptop says that 104 GB are in use. I've checked the properties of the folders (not the hard drive itself), even the hidden ones, this says that only 31GB of files, folders, programs are busy.

Where are the 70GB files hiding?

It may be that they are occupied by reserved memory (for the operation of the laptop). Googling "Freeing space on Windows 10"…

Once the disk cleanup is running, then shadow copies and old savepoints are gone too:

https://support.microsoft.com/...sk-cleanup

Of course I have already tried, CCleaner too. Hardly any changes.

It turns out that the problem is Windows backups. I deleted it and now I have memory again.

CCleaner is scrap. Do you have to do it manually?

That should actually make the disk cleanup, if you also select "clean up system files".