I had a few PCs that were updated from Win 7 Pro to Win 10 Pro during the initial offer period. They have been running Win 10 since.
Recently, I noticed one of them could not update itself from version 1803 to version 1903. It just failed, and never provided a reason. I took it as a challenge to solve, but numerous troubleshooting methods failed.
I decided to reinstall Win 10, but with the option to keep all apps and files. Nope. It did not work. OK, how about just keeping files and wiping out all apps. NOPE! What the heck? It said "Cannot update to Win 10. Your system has been restored back to where it was". No blank screen. Just stuck forever at 1803 version.
I decided to reinstall Win 10 from scratch, but onto a new SSD that I was going to migrate to. This way, I still had the old HD to go back to, if the fresh install did not work. Win 10 installation recognized the hardware, and honored the digital license of the previous installation. Seems fine so far.
On another machine, the migration from an HD to an SSD failed due to a bad cable. Rebooted to the HD, and Win 10 managed to trash the HD while booting due to said bad cable that I did not know to replace. Repeating crashes during boot, but with different error codes given at each BSOD (blue screen of death). Tried to reinstall Win 10 with the option to keep all apps+files. It worked this time. Hah! I then managed to migrate to the SSD this time, but with the cable replaced.
Computer software is getting so complex, it's like a living organism. No two persons age and die the same way, not even twins. How did the digital world evolve to this state? I think it is alarming.