“To reiterate, this issue is only impacting our players on Steam,” ZeniMax posted yesterday in the dedicated forum thread. “We’re actively working with Steam to get this resolved as quickly as possible.” The support Twitter said the team was on top of the problem 15 hours ago.
Why not just follow the workaround, which is to run the 64-bit client buried in Steam’s files? You can, but only if you’ve previously linked your ZOS account to your Steam account, only if your account is old (according to Reddit), and only if you’re not subbed; apparently, if you’re subbed, you’ll lose that sub. We’re pretty sure Bethsoft will sort that out eventually, but in the short-term, it’d suck.
— Bethesda Support (@BethesdaSupport) February 15, 2018