Re: Sims 4 starting up in a small window
@wazves Does this still happen if you play in windowed fullscreen? Even if you prefer standard fullscreen, it would be helpful to know.
Either way, please try disabling any other apps that come with overlays, for example Steam or Discord. Even if the apps themselves aren't open in a separate window, check the Task Manager's background processes list for any associated services that might still be running.
If this doesn't help, please try playing in a clean boot.
When you reboot, check the Task Manager again for any processes that don't absolutely need to be running. If you accidentally kill something critical and it doesn't restart on its own, just reboot your computer.
Additionally, if you use the EA App (and I do see Origin in your screenshot, but some people use both), do NOT disable the EABackgroundService, or else the App won't open.
I realize that testing can be a bit tedious when the problem doesn't happen all the time, but this isn't a common-enough issue that I can give you a list of known causes.