After almost a year on two machines Win10 forced me to do a clean install after not booting after an update. First the update wouldn't install, then when it did it booted to a BSOD then the repair disc wouldn't repair anything or find my clone or perform a clean install.
I might have made it worse on myself as I didn't know about the differences in MBR and GPT partitions and the need to have GPT to boot from UEFI but I got it sorted out. I think that was also keeping me from seeing my OS clone because it was on an MBR partition and I was booted in UEFI. Now I have the OS and it's clone on GPT partitions and everything else on MBR.
It was a PITA but not that bad as I only had to reinstall the OS and a few apps. Thank God for having apps, data and backups all on separate drives (6 partitions on 4 physical drives).
And I still like Win10.