Hello there @Flame!
Yeah, this is a tricky one. Encountering “Assertion failed: !Object->HasAnyFlags(RF_NeedLoad…” on startup has popped up a few times around the community. The usual solution is to isolate the cultrip element and either fix its functions, or replace it with a new asset, but you have already tried that.
Checking your log with my peers, the crash boils down to a loading crash when accesing properties like UUserDefinedStruct::Serialize and UUserDefinedStructEditorData::ReinitializeDefaultInstance. That suggests that the cultrip is tied to UserDefinedStruct elements.
Most likely, UE is trying to read a UserDefinedStruct that’s either corrupted, out of sync with Perforce, or containing invalid references. Since the whole issue started from a reboot, it’s possible that the structure was affected due being modified while other components using said struct were still loaded in memory.
So, it all boils down to continue testing isolation, focused on all UserDefinedStruct. Please test the following:
- First of all, backup your entire project
- Next, in Perforce, list the recently changed .uasset files, and check for the ones with update time close to when the issue started
- Then, revert those files, and try launching the editor again
- If you are not fully sure on which assets to affect, try reverting ALL UserDefinedStruct assets
If the issue persists after covering all the struct files, then the remaining path would be to batch-migrate your content to a new, blank project, in order to reconstruct it. After each batch, open the new project and test it. If you encounter a crash at some point, then the issue’s cause will be included in that batch’s content. It’s a slow approach, but it should give you results.
For further reading, and other possible methods for resolution, please check the following threads: