UE5 Crashing upon opening heavy level

Hi everyone! I have a UE5.1 scene that has quite a lot of lights (maybe like… 25?) and a fair few heavy assets (although it’s manageable). It’s been running fine so far, no hitches at all, but today I go to tweak one light/asset and it crashed. After that, each time I open it up (the level, not the project), it crashes. Here is the crash report:

LoginId:6aea355a4dc757c22f3cd9b2200baa2a
EpicAccountId:be32ce5a19744dae98b4c517fcca8457

Assertion failed: InIndex >= 0 && InIndex <= kNullIndex [File:D:\build++UE5\Sync\Engine\Source\Runtime\RenderCore\Public\RenderGraphDefinitions.h] [Line: 327]

UnrealEditor_RenderCore
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Renderer
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_RenderCore
UnrealEditor_RenderCore
UnrealEditor_Core
UnrealEditor_Core
kernel32
ntdll

Anyone know what the issue is and how I could go about solving it? Thank you so so much in advance!!

If the engine only crashes for you on a heavy level you are one of the lucky one’s. For me (and many many others) it crashes constantly, even in almost empty scenes. I also could pin point the problem. As with most games it is DX12. That API is just broken. If i change the API to Vulkan i can work in the most complex scenes the entire day without a crash but as soon as i switch back to DX12 the crashes start to happen again. The only problem is that Vulkan has its own myriad of problems (at least in this engine), Megascans turn black, performance cut in half etc etc. If i were you, i would not get my hopes to high up to recieve help from Epic or that any of the problems get fixed. It’s been that way since the initial release of version 5 and epic simply does not care. I’ve sent them ~4GB of logs and crash reports and did not get any response out of them. They just don’t care. Just look at the market, there is not a single released game anywhere that uses UE5 (apart from some very low effort indie projects), yes there have been trailers but thats all we’ve got so far and i’m starting to see why. Every dev team that stated that their upcoming game uses UE5 has gone radio silent except from a first inital trailer which most likely did not even run in-engine. Even the newly released Dead Island 2 uses a heavily modified version of UE4, and now guess why that is. Most of the new features are broken or not even remotely close to production ready. I’ve given up all hopes that they will fix anything. If anything they will continue to break it. All the bugs from the 5.0 Preview are still in the latest 5.1.1 (and the 5.2 preview), they just add new features without testing them on a wide range of hardware. I did a full playthrough of Cyberpunk with the new Path-Traced Overdrive Mode without a single crash but UE5 keeps crashing upto 15 times in a single hour. Memory Leaks, reproducable bugs and weird workarounds are the norm with this engine and it will most likely stay that way (at least from what we’ve seen so far)

I had a similar issue and it was caused the the rendergraph getting too many passes added to it from the landscape editor due to the size of the loaded terrain. As a workaround I swapped the FRDGPassHandle type from uint16 to uint32 (and altered some asserts checking for uint16) so it process all the passes.