"I think you will have to install EaseUS on Win 10...to be able to successfully make a backup of Win 10."
I thought about that too, but I am doing a disk/partition backup, not a system backup. Don't...

I appreciate your hints... thanks.
This is not about how to prevent loosing data (my original disk is safe, on the table, I also have an EaseUS emergency disk) or how to recover it. I started...

40 to 50 GB

What you are saying is correct. It's another way of doing things. There is no issue with a windows key or licensing involved.
And still, why a backup cannot be restored is a mystery...

The B3 and B2 backups, and also another one that I took right before B2 are all hanging when trying to restore.
Initial B1 is fine.

Oh, but there is no System Reserve in my case (which would be required), it's only the Recovery partition that got added with the upgrade. So backing up only the system partition is correct.
309131...

Thanks for your help... this may explain it.
I was living with the idea that the System reserved is disposable and that it contains only the windows recovery files (didnt even bother to back it...

So I backed up two different Win10 branches originating from the same Win7 starting point.
B1 = the Win 7 backup, used as a starting point
B2 = a Win10 partition backup, resulted by restoring B1,...

I am using the free edition of EaseUS ToDo Backup and run into problems with restoring in a specific situation.

I was doing regular full backups of a Win7 system partition, located on Disk 1 (not...