Sometimes when I exit out of the sim by using Alt-F4, the sim continues running, though it does not show anywhere on the Apps bar. Sounds can still be heard also, like if one was in flight, the engine running, you continue to hear the engine. It is about 60 to 65% of the time that this occurs.
If I try to go back to start screen after a flight, the simulator freezes, stuck in the ‘reloading main screen’ mode with the view of the Cessna 172 over those green mountains. The progress bar stuck at about 90%. I have waited for 5+ minutes for it to get to main menu before quitting.
If you run into this, does your sim never close / return to the main menu or does it just take a really long time? Check in task manager if your RAM is (nearly) full while this occurrs. If content from RAM is swapped out to disk, it takes magnitudes longer to access that data.
Although exiting with ALT-F4 does work, that is probably not the best way to close MSFS. It would be a bit like shutting down Windows by pressing your computer’s power button. I’m not sure if all running processes in MSFS will exit cleanly, and all open files will properly close if you just ALT-F4.
I always exit MSFS by returning to the main menu, and using ESC to bring up the close dialog prompt.