I managed to resolve this issue, so I will post the solution here for anyone who might have the same problem in the future.I'm having this exact same issue.
The game was running fine until there was a power shortage in my region while I was playing.
Now every time I open the game, this fatal error comes up and it immediately crashes.
I'm guessing there is a corrupted file somewhere, but I already tried to re-install the game and I've also deleted the Underthewitch and UnrealEngine folders from my Appdata without fixing the issue, so I don't know what to do.
Here's the error:
Fatal error: [File:Unknown] [Line: 729]
BulkData compressed header read error. This package may be corrupt!
Anyone know what I can do?
The name of the exe of my game was "Lake", so I had to delete the C:\Users\(name)\AppData\Local\Lake folder instead of UnderTheWitch folder, which I had tried previously. After I did this, the game ran smoothly.
I had downloaded it in a different site, so this solution might not matter to users here though.