I need help (world partition is not enabled for this map)

I just got unreal and was just messing around and did something. I’m not sure what I did then I got this. Every project I start afterward pops up with this. I can get the third-person world thing to come up anymore. I tried uninstalling it and then reinstalling it but nothing changed.

Try, In the main editor window:

Window → Load layout → Default editor layout