A family friend (lawyer) came to me with a laptop a couple weeks ago. She has all Macs in her office, except for one Windows laptop that she uses for a specific piece of software.
After refusing Windows 10 updates for ages, it finally decided it was time to upgrade itself, and it went badly. It got stuck in a boot loop with the Windows 10 update only half baked, and I couldn't find any information about reverting to the previous system without actually being able to boot into Windows 10.
I worked on that stupid laptop for hours trying half a dozen of the least destructive solutions first, but finally I had no choice but to put the laptop back to factory settings. Thankfully her software vendor had excellent support and was able to tell me exactly what needed to be backed up before wiping the system.
I don't see how Microsoft can, in good conscience, be so heavy handed about an OS upgrade, especially without some method to revert to the previous system if the upgrade goes badly which is not an uncommon occurrence.