Yep, just updated today and it totally broke Steam. I also cannot downgrade back to 7 now because it created some phantom account so I am pretty much screwed and now have to reinstall 7 and about 12TB worth of games. Thanks MS, never touching 10 again. Worst OS ever, and I will make sure that that my 60,000 workstations never see it after this experience.
The issue described in this thread has long since been resolved. I'd recommend either explaining what the problem is or searching for people that have similar experiences if you intend on trying to fix it instead of writing off the OS in a huff.