This is all I have to do to resolve this Error message.
1-Click on Launcher, launcher opens with Error Message 209
2- Close error and Launcher and reopen. Repeat Step 1 if you receive the error again.
I think the most times I had to close the error and reopen the Launcher before getting "Play" was 3-5 times MAX.
I've NEVER had to repair the game, NEVER had to run as Admin, NEVER had to run from Eso.exe or ANY OTHER fix.
I've done that for the last two days and when I logged on this morning, viola, NO ERROR MESSAGE anymore.
More than likely they will have to "re-design" the Launcher and until they can get resources to do that, after the console release, we'll have to make do with it as is.
Save yourself a lot of headache and try the above......
I hope it works as easily for you all as it does for me.
NA Server - Kildair