Failed to load's problems (UE5)

Hey, everybody. Sorry, I’m a newbie, maybe this is a dumb question or an obvious problem. But it’s blowing my mind and I can’t find an answer(

I made a project set up lighting, fog (EasyFog) camera and lights. Everything looks good and works fine. Saved, went to work hoping to render in the evening)
But when I come back and open - all gone. All light - “failed to load”.
Fog just turned off. WTF?)
Experienced friend says - it may be related to the “world partition”. I loaded the cells - nothing helps.
Does anyone understand what is going on?
It’s just a my bad luck and random UE bug, or it’s common problem and I can fix it?

Thanks !

If you could post the error log, it would be more helpful. It could be a hard drive corruption, or something that EasyFog caused? My fantastic Advanced Fog doesn’t have those issues :wink: