“displayname registry feild missing”

barrub24yanv  I wouldn't say there's nothing you can do, only that I personally am out of ideas for the moment.  I'll keep trying though.  What fixes the problem in the end may be an EA App update, of which there are a lot.  I've seen many problems related to the App that are not solvable from the user side, and while there's always something, the problems themselves keep changing, and so do the users affected.  So it's very possible that this will resolve at some point even if you do nothing.

If you want to be as thorough as possible, use the new admin Windows account, and disable your antivirus when reinstalling the EA App and Sims 4.  Don't reenable it until you've tested the game.