Upgrading to WIN 10 is a disaster.
I took the option to upgrade with 3 PC's. Within a few minutes of looking at this distasterous product on all 3 PC's I discovered a wide range of faults and failures including such as killing the internet, disabling programmes, altering configurations etc..
2 PC's took about 20 minutes each to install WIN10 but my main PC took over 7 hours so I knew it was going to be a disaster. It did serve to identify that the upgrade package was filled with faults.
In all three cases I chose to do a roll back. In all three cases the roll back was a total failure to such an extent I had to reinstall backup WIN7 OS's.
Of course, because it was Windows, there was 100% chance it would fail to update properly and a 100% chance it wouldn't be able to roll back successfully which is why I did the backups. (Why do I do OS backups? Because on dozens of tests the WIN restore programme has proved totally incapable of restoring. In fact I've never gotten a successfully restored comment from WIN which is why WIN restore is disabled on all my PC's.)
I have absolutely no doubt that they can perfom an upgrade in a court room to almost any PC and that upgrade will have major destructive flaws. And if they roll back it will be a PC full of bugs. So any comment from Microsoft will easily be proven false.
I think the phrase "I had a successful upgrade" could be attributed to not knowing enough about PC's to be able to offer a reliable comment.