TS2LC: Stuck on borderless windowed, can't get fullscreen or change resolution

Thanks, does this also happen on a brand new save file? 

You can move the saves to your desktop from Documents > EA Games > Sims 2 Legacy > Neighborhoods to test this. 

This did not work. Still occurring:

1. I am able to press the windows key and bring up the taskbar/open other application on top of the Sims 2, but switching applications causes the game's audio to mute. Thankfully, the game still runs and does not freeze.
2. In-game window resolution options still grayed out
3. Alt-enter does not work and causes Windows error chime to play

Thanks SimsMegaDeluxe 

Can you try deleting the config folder in Documents\EA Games\The Sims 2 Legacy\Config?

The graying out of resolution is expected if you are in borderless windowed or maximized windowed since we can't override OS level settings.

Yes, it's definitely borderless windowed.

This is my resolution.

Update: for some reason I can now open application windows and they appear on top of my Sims 2 game. I think I might be in fullscreen windowed.

Still, the in-game resolution settings are grayed out and Alt-Enter still doesn't work (plays the windows error chime).

Thanks. Could you tell me what resolution your display is in the Windows display settings?

No, this doesn't work. The game still launches in fullscreen mode with Alt-Enter and the in-game resolution options both not working.

Heya SimsMegaDeluxe

Can you try the steps puzzlezaddict shared here please and let me know if they help?

Please try forcing the game to run in windowed mode.  For EA App installs, open the App game library, click the three dots in the upper-right corner of the Sims 2 Legacy icon, select View properties, and add -w to the command line box.  For Steam, add -w under Sims 2 > Properties > General > Launch Options.

Is this only a Steam issue?

I checked Steam Discussions. Other people are having this issue: