genius, it worked
I had a similar issue — and it looks like I finally solved it!
I was getting this crash after any change to a Blueprint — adding variables, modifying components, logic, or even just moving things around. If I hit Play without compiling first, Unreal Engine would crash with an error like:
EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000000
I don’t think the issue was related to bad logic or invalid data. Even with proper IsValid checks and safe casting, the crash still occurred. It happened even after very minor edits.
Apparently, the reason was that Unreal sometimes runs a stale or partially updated version of the Blueprint during PIE (Play In Editor) if you don’t manually compile it first. That causes the engine to access objects that don’t exist yet or are in an invalid state — which triggers the crash.
The solution is kind of silly, but it works:
- Always hit Compile before pressing Play. Even if you made just a small change — compile first, then run. Otherwise, there’s a risk of a crash.
- Disable automatic Blueprint recompilation before PIE. I went into Editor Preferences → Blueprints and unchecked the option Recompile Blueprints on Load. Now, if I forget to compile, the game won’t start, and I’m reminded to do it manually. Much safer this way.
In my case, this completely fixed the issue. Hopefully this helps someone else avoid random crashes that don’t seem to have an obvious cause.