My project worked fine in 4.27 and 5.0.3, but now that I’ve upgraded to 5.1 I can’t load any blueprints or any levels with old blueprints in them (so all of my work so far). I can create new levels with new landscapes, I can drop in some old blueprints like my sky and ocean, but I can’t edit any of these blueprints, I get the same crash over and over (screen shot below).
My installation of 5.1 seems to be fine, I can create a blank project and edit everything in there, and my drivers are all current.
Here is a snip of the crash reporter. The message is always the same:
Hey there @ideefixe! Sometimes when upgrading projects, conversion can cause all kinds of whacky effects. Is it always the Niagara effect error, no matter whichever BP you edit?
Yes, I get the same error, even if I try to edit a BP that doesn’t have a Niagara component (like the default Third Person Character). The error doesn’t come up if I use a clean project so I don’t think it’s an install problem, and I can create new niagara systems/emitters and they work.
The blueprints will load, and as soon as the editor opens everything crashes. I’ve also tried migrating some of the blueprints to a clean prpject, but it crashes during the migration.
Hrm, let’s first try to wipe the cached data, (which doesn’t usually fix this, but is worth a try since it fixes a couple of migration issues). Back up your project, then move/delete these 3 folders:
Then relaunch and let them be remade and try to continue.
The last time I saw someone run into this issue, it was related to a specific BP that needed to be deleted then everything ran fine. I couldn’t tell you why, since it references a Niagara system.
Hrm, this is a tough one. It’s likely going to come down to finding the offending system and scrubbing it, but that’s tedious to say the least. If possible, back your project up, sort all (content side) Niagara systems you have. Are there any that ask to be saved every time the engine launches? If not, you may have to look into each and see if one being checked crashes you. It’s odd that you’re crashing on all BPs, the last time I ran into this one, the user had went through (and this is no joke) and deleted BPs one by one to find the offender, then reloaded their backup and scrubbed and remade that BP.
I started doing that yesterday, I’m opening one by one and seeing what crashes. I’ve noticed I can open some interfaces but not others, so I’m trying to isolate the problem ones!
Also, I think I already know the answer, but is there a way to downgrade the project back to 5.0.3? It worked back then, but I upgraded without creating a backup (amateur mistake). It’d be nice to get it back to a working state and then debug from there.
Oh my god, I think I figured it out. It was the 2D fluid sims from the Niagara fluid content examples. I pulled them out and now everything seems to work. Thanks for talking it through with me!
They were migrated from the Content Example project; I brought them over to play around with them a little bit. I haven’t tried to rebuild the fluid systems using the engine examples or from scratch yet, for now I’ve reverted to the previous Niagara systems I was using!
