I figured out that it was being caused by a faulty sync partnership - which is another rat's nest of unhelpful information from the overlords of computing.
Disabling sync center / unmapping network drives seems to be the fix for me
Again, in my view this isn't about chkdsk,, sync center, or anything - its about bad UX design (which is all about creating and managing user expectations). Your stupid little balloon told me restarting would fix the problem, and it does NOTHING. the problem is more complex than restarting, obviously.
If you had said, "there is a problem with a drive, and it may be really complicated to fix" I would have had no problem with that. I would have waited until I had 2 hours to spare to delve into it and known going in that it was likely to be complicated, obscure, and frustrating. Instead you set me up with the expectation that this would be easy and then utterly failed to meet that expectation.
Please forward this to your UX team with the headline "You should be ashamed of yourselves"