I ran into the same issue (that Jason talked about, freezing / crash when opening World Partition Window).
Adding a dummy placeholder mesh into some blueprints i had (where a static mesh was set as an official variable), fixed the issue initially.
Then however, as i zoomed out, it froze.
My world is a prototype large open world map with enormous scales for a skybox and distant planet, so i figured those elements may have had something to do with it.
But even deleting EVERYTHING in the entire level, it still crashed.
Now, somehow, it’s fixed.
Here’s what i did.
- Rebuilt all levels with HLOD0’s
- Crashed the editor as it tried HLOD0’ing the millions of km of skybox / planet.
- Restarted editor, rebuilt all levels, deleted HLOD0’s
- Actually read up on data layers. Added a new datalayer in which i assigned the planet and skybox. Edited datalayer file to affect runtime. Set them to always loaded.
- Went into the individual skybox / planet blueprints / meshes, set everything related to collision or streaming to off (apart from virtual textures), or set relevant settings to always awake.
- Unchecked the new datalayer from editor and set it to unload in runtime.
- Played in editor. Stuff was correctly unloaded.
- Changed back to always loaded in runtime and editor. Saved All.
- Played again.
Saved All.
Moved random actor, ctrl z.
Saved All again.
Now, somehow, the world partition window works. No crash or freeze.
No clue which step did it.
From my guess, it was adding a datalayer so the engine had any clue how to deal with the enormous meshes surrounding the world.
I would suggest, adding a datalayer at all (instead of literally nothing), could solve it. But i dont wanna presume the others here are as incompetent as i was.
Just hope this helps someone.