Hey there,
I too am experiencing the Error 210 as outlined in the kb article
https://help.elderscrollsonline.com/app/answers/detail/a_id/22414/
I have followed each step as described however i am still not able to resolve the error and update. in addition to the manifest file fix, ProgramData fix, run as admin fix and repair fix, I have also removed eso completely from my computer, rebooted then reinstalled through steam. I've been having this issue for roughly 24hrs now.
I also tried to open a ticket and email to ESO_Help@helpmail.elderscrollsonline.com but it got closed as a duplicate Question Reference # 170902-003461
I see forum admins taking affected users gamename to look into. mine is Jellomold.
Please advise on my next steps. Would like to return to playing.
Level 35 Nord Stam DK