I'm experiencing an issue with the update via Steam as well. OneDrive is unlinked and not running. I don't have an "unsupported file system message." The download appears to be done (538.9 MB / 538.9 MB), but it's still writing to disk, and Steam estimates about 1 hour 31 minutes until completion. I've read about (but not experienced) Steam issues on the day of release. I think Steam's infrastructure is having trouble dealing with the huge demand for the update all at once. Hopefully they can learn something from this and improve things for next time.
Edit: It took the full two hours, but my game finally updated.
At least you only have to wait an hour and 31 minutes. Mine was estimating that it would take 1 or 2 days.
