Unreal Engine was started in background, I just messing with something and unexpectedly UE crashed. After somedays I just try to open crashed project and now stable receive this message on startup. Unreal Engine 5.6. Already tried to remove Saved, Intermediate and DeliveredDataCache folders. Any ideas how to fix?
So, after several tries I find tricky solution. I delete the VehicleAdvGameMode, then when the editor already loaded, I reset file and in 2 of 10 tries I can open it. So, I just create new GameMode and copy everything from VehicleAdvGameMode when editor didn’t crash (I don’t know why some times it open it and didn’t crash). And one more thing, I found a strange field “Thumbnail” in broken VehicleAdvGameMode (in my new one with the same parent it not appear), so I think this is was the one of the things what cause crash.
7 days ago, I just continue messing up with project and the problem get back again( So, now it appearing when I try to open “List of world Blueprints available to the user for editing or creation” or try to open recreated Game Mode - Unreal Engine just crashing. I don’t know why it become happening again, cause for some days everything was fine. I didn’t touch GameMode after previous fix. Callstack looks really similar, but not the same:
So, I tried to reset to the stable version of file which 100% worked from source control and… Unreal Engine now crashing and with this version of file…
P.P.S. Tried to remove Saved, Intermediate and DeliveredDataCache too
So, only one worked way was rollback fully to previous stable commit. Loose 2-3 hours of work, but save the most part of
Crashes get back again after save all properly and restart editor… When I try to open GM, or any tabs or menu where using GM, editor just crashes
P.S. Interesting moment, yesterday when I completing my work I opened Class Settings and saw this “Thumbnail” field again, but everything had work fine and I just didn’t pay attention to it. Now I roll back to previous stable commit and this one don’t have “Thumbnail” in GM Class Settings. I don’t know in which moment, but this looks like this parameter appeared and broke something
Hey there @Georg1000! Welcome to the community! This error is definitely pointing to the GM, and has the hallmarks of GM corruption, but seems to be stable outside of that context. Is this from the updated advanced vehicles template? Do newly created Game Modes have this thumbnail field?
Current “broken” GM was created in 5.5, so, it’s from previous advanced vehicles template. If I try to create new one thumbnail field will be not exist. It appeared only after copying nodes from broken GM into new one and after some restarts of Unreal Engine. Some restarts it can be still stable, but in one moment just become broken
So, I opened broken GM in newly created project and recreated everything in my project in newly created GM and everything work fine and nothing crashing, so I think problem was in one certain “broken” GM. If you need something to figure problem, I saved broken GM and have a version of project in broken state, feel free to ask if you need something for debug.
Sounds like it was just migration corruption, in cases like this remaking the class in a functioning instance is often the best way to go, since blueprints are binary files there’s not often much to do when they corrupt. Thanks for the update!
If you will ask me what I done… Nothing… Absolutely nothing… Only commit new changes in git and just open Unreal Engine after several days of idle. I tried to close and open Unreal Engine sometimes before I wrote previous message everything was fine, but only on this try when I open it’s start crashing again…
So, I delete GM and open Unreal Engine, try do touch everything and all works fine, than I reset file which was deleted and can open it and even start game! So, than I save everything and close UE than open project again aaaaand it’s broken again… I just try to open something and UE crashed until I delete GM… I don’t know what to do now… May be something inside of my GM caused this failure… I can share the screenshots of my blueprints, if you want
P.S. Interesting moment but in that iteration of GM “Thumbnail” field, doesn’t appeared.
So it’s more likely that the GM failing as the core of the error is a side-effect of what’s occurring since it solves it before it’s written again. I would definitely take a look at the blueprint but it’s not usually the case when it’s making core engine assertions.
Wow, something new was appeared. If I create new absolutely clear GM with Game Mode parent, change only default pawn and default player controller and apply it to default game mode, UE start crashing with it. I will continue experiments
I tried to repeat this on fresh GM step by step(I try to add controller and than restart UE, than add Pawn and restart, than apply to default GM) to find which definitely what breaks UE, but… It was not repeat… I’m out of ideas
So, I found connection! Every time when I delete GM, cast to GM node in VehicleAdvPawn (attached screenshot of broken node) become broken, so, now I tried to recreate everything and when I added this cast - it becomes broken… I don’t know why but definetely cast from VehicleAdvPawn to GM break UE.
So, this sounds like 100% bug, I moved this cast in PlayerController and now everything works fine. I don’t know why it’s becomes broken when I cast form Pawn to GM
That is quite interesting! Generally this Bad cast node would come from the class not existing or not being read at the time. After checking over the BP itself, I don’t see anything that could cause these effects.
The Get Game Mode node having an error is odd because there is always a GM, even if it’s the default. Does this still error out if you’re just printing the GM’s name itself from the Get Game Mode node?
Is this pawn in the persistent level or a sub level?
I haven’t been able to reconstruct this issue just casting to GMs that inherit from children or GM base itself. It’s possible the engine installation could have had an issue but very unlikely as this affects binary files, so I’m also leaning on bug.
