A Microsoft file hosting and synchronization service.
This is just irresponsible the way this failure has been handled. MS starts charging more for our 365 Family Plan and at the same time degrades their cloud storage by no longer supporting local sync of shared folders. Evidently, they know full well that they've broken OneDrive, yet they don't bother to send an apology or just a heads up to paying customers that the failure is on their end, so customers at least know what's happening. How many hours have people wasted trying to figure out how to fix a problem that can't be fixed because MS broke it on their end. It's disrespectful.
And how can it not be fixed yet when it worked for years? It's scary to think that I'm trusting my data with them in the face such incompetence...