Painter crashes every time I try to open a certain file that opened just fine earlier

Heyhey, guys!

I am a bit frustrated right now because my Painter keeps crashing whenever I try to open a certain file. It's not just that file, though, but also all autosaves of it (going back about an hour before the last manual save). It opened just fine earlier today and I had no issues with it at all so far. An older version (basically without actual progress, though..) opens without issue as well.

So far, I have restarted my PC, updated my graphics driver, made sure that Painter launches using my GPU, moved the file from my external hard drive to my local one and tried to run Painter and open the file without anything else running at the same time (to make sure all resources are reserved for Painter). Nothing has helped. It just crashes about a second or two after I try opening it. There was one instance where it took a few seconds and it looked like it might be loading the file, but it just crashed again after a few seconds.

I didn't even do anything overly fancy. The only things I could imagine causing problems are that I was working in 4k, which does lead to lagg sometimes (but shouldn't crash the file...) and that I created a very, very simple (literally 3 nodes) custom material in Designer that I then brought into Painter as well. Anything else is complete standard. 

Any help would be much appreciated!! If uploading the file or so would help I'll do that!