I'm experiencing the same issue as @lozzajanex2 and @Fabius_SimTube. My game launched perfectly fine until yesterday, and today TS4 and TS3 wont open because they are 'already running'. I used different methods for troubleshooting, but the only thing working is setting my computer date back to june 1. (I only jumped two days forward in time, non working.)
I also logged into my account on my gaming laptop and the game starts without issues.
@keinluigi Does it help to simply remove UserSettings.ini, inside Documents > Electronic Arts > The Sims 4? This is the file that stores data on the daily login rewards you've claimed, and the only thing I can think of that would be sensitive to dates starting a couple of days ago.
@keinluigi I don't understand either, but three people in a short time frame suggests something strange is going on, and that was my first thought. It would still be helpful to confirm that the files in your Sims 4 user folder aren't related to the issue, i.e. by removing them temporarily. If nothing else, it will help eliminate some possibilities.
