Why do my Unreal projects keep breaking?

I’ve had 4-5 projects stop working for no reason. I’ll be using the engine and simulating normally, then all of a sudden, when I hit stop it makes a strange noise. After that the project doesn’t work anymore. No crash report or errors or anything.

This happened to two games I was working on, and 3 times as soon as I reach the crouch section of this tutorial series (https://www.youtube.com/playlist?list=PLL0cLF8gjBprG6487lxqSq-aEo6ZXLDLg)

After the project makes the strange sound, it never plays properly again. Permanently broken, won’t possess the character.

This is very discouraging and I want to just understand what I’m doing wrong, or what is happening