This is the very same problem I had with the 1st gen clickwheel iPod. When I first connected one to a new computer, iTunes asked me if I wanted to 'initialize' the device. Oblivious of its meaning I went with 'yes' and wiped a borrowed iPod clean. Friendship ruined forever.
If so, that's not a UX problem. That's a flat-out bug. In short, there was an option to migrate files from folder A to B. Months later, in the update, folder A was accidentally deleted. The migration would decrease the damage, but not prevent it, and saying 'no' is not a mistake.
Sounds like Apple just doesn't learn some lessons.
However this behavior is really out of the line for MS since they've got a good track record on backwards compatibility and data preservation. Previously during in-situ upgrades the installer would back up gigabytes of data in a special folder on the off chance that they might be needed again in the event of a rollback, and somehow they managed to drop the ball this time round.
I've had some problems, but then again, I expect my computer to do weird things sometimes, I guess that's expected if you're a software engineer :p
To hear the recent stories of updates causing issues is surprising, but with so many supported configurations for Windows, I find it a lot more excusable than MacOS or ChromeOS.
That doesn’t mean things like this shouldn’t be caught in QA, it just means it’s not always easy.