Re: EA App states game is already running when it's not
@LadyLucinaTwitch Try moving the entire Sims 4 user folder (the one in Documents > Electronic Arts) to the desktop. If you get an error when trying to move it, or it copies rather than moving, stop here and let me know.
Otherwise, try again to play. If you see the same error, restart your computer, then pause OneDrive syncing, that is if OneDrive is running at all. To see the option, right-click the cloud icon in the lower-right corner of the screen.
If that doesn't help either, please set exceptions in your antivirus for TS4_x64.exe and EADesktop.exe. Even if you only use Windows Defender, Controlled Folder Access might be the problem, and you can set the same exceptions. Don't enable it if it's not already running.
https://crinrict.com/blog/2019/03/windows-10-defender-controlled-folder-access.html