Ok, thanks! I’ve already deleted a whole lot with no result. I’m just going to keep trying that and hope I find the corrupt blueprint. If not I’ll be back here in a few hours. 
What I don’t understand though is that even when I try to open a camera shake which normally has not a single reference to anything of my own blueprints it causes a crash. So I don’t know, but could that mean that the problem is caused by something greater than my own blueprints?
Update: Ok I’ve removed ALL blueprints in my project and the crash still happens.
I’ve created a completely new blueprint based on actor and opening that newly created actor also crashes the editor instantly.
Also materials are not affected, I can still open all my materials just fine. It’s only blueprints, everything else still seems to work.