Yes, this is on 24H2. I’ll be curious to see if that gets resolved by Windows and/or Nvidia, though I don’t have this same issue on 5.4, so to me that’s more indicative of something inside UE 
Can’t you try to uninstall last update? (Not sure if possible, anyway)
What drivers are you on? The latest drivers are 566.36 and I want to say the whole 56X branch had some workarounds for sync issues with 24H2.
For instance, from the reddit post for the 566.14 drivers:
- Windows 11 24H2 requires MPO support enabled to reliably support DXGI window capture, this impacts applications such as Lossless Scaling and Magpie when using DXGI to capture
- Windows 11 24H2 ALT-TAB black screen is a Microsoft Issue and fixed in KB5046617 (November 12th) - NOTE: may break hardware composition / hardware flip and still be a gradual feature rollout
- Windows 11 24H2 on some systems have crashes when launching games, stutter issues, RTSS related crashes, exclusive fullscreen game ALT-TAB issues and crashes with overlays enabled in games. Other GPU vendors (AMD/INTEL) are also impacted
- Windows 11 24H2 WDDM (Windows Display Driver Model) 3.2 and DirectSR (Super Resolution) driver support officially started with the 560 mainline releases
Also, any apps that can do overlays might be causing issues, even if they aren’t enabled. Like for instance, if I accidentally leave RTSS graphs running and open UE, it causes chaos and I’ll have a bunch of graphs popping up all over the place (even the editor loading screen before the editor opens). Check every running app to make sure none of them have overlays enabled.
Looks like Lumen works wrong in some GPU’s (like set “Medium” GI Scalability settings, but on “Epic”):
P.S. Looks like problem in Distance Fields Ambient Occlusion in shadowed dark areas when SkyLight is Movable. Lumen just hide this problems. But I don’t understand, why no Lumen on non-RTX GPU now?
Perhaps the Weirdest and Worst Bug yet, You can’t Retarget the main Motion Matching Anim BP in 5.5 for some reason. I had to revert to 5.4 just to do this…
UPDATE
The 5.5.1 Hotfix is live with a selection of key fixes!
| Issue | Summary |
|---|---|
| UE-230698 | Crash when creating a child blueprint based on a dirty blueprint |
| UE-229712 | MovieGraph: Crash when using BurnIn + 32 Bit PPM to Single Layer EXR |
| UE-230710 | [PCG] Crash when double-click on an inspected point in Collision Wrapper data |
| UE-229151 | Crash in OpenGL-only build on an Android 14 Xclipse-based device causes a shader compiler crash |
| UE-229659 | Collision wrapper can crash with meshes that don’t have a proper body setup |
| UE-230984 | Possible crash when the active camera rig is frozen |
| UE-231280 | MRQ Graph - Avid DNx plugin does not compile in shipping builds |
| UE-231082 | MovieGraph: Crash with ObjectID pass |
| UE-229447 | MovieGraph: Crash when rendering with Additional PPMs |
| UE-231174 | Motion Design Rundown (game mode) Crash with BP modifiers |
| UE-230366 | An Assert occurs when resetting a response curve with keys used for a Utility Weight in a State Tree |
| UE-229250 | DirectX 11 crashes with -Renderoffscreen |
| UE-230359 | MM Database crashes if adding an animation to a pose schema that’s linked with no set skeleton, or a differently set skeleton |
| UE-230330 | Delete Attribute node causes Crash |
| UE-229146 | Crash enabling Lumen visualization on consoles |
| UE-230583 | [CrashReport][Assert] UnrealEditor-InterchangeEngine!UInterchangeManager::ReleaseAsyncHelper(TWeakPtrUE::Interchange::FImportAsyncHelper,1) [Engine/Source/Runtime/Interchange/Engine/Private/InterchangeManager.cpp:2638] |
| UE-227658 | [CrashReport][Crash] Unknown() Address = 0x19a5af0ac (filename not found) [in libsystem_kernel.dylib] |
| UE-226339 | [CrashReport][Crash] libpython3.11.so.1!7f1e67200000 + 239c80 |
| UE-195187 | [CrashReport] Assertion failed: UsedStagingBuffers.Num() == 0 |
| UE-228298 | MAC - Substrate - Crash with sm5 |
| UE-230578 | [CrashReport][Crash] UnrealEditor-CoreUObject!UStruct::IsChildOf(UStruct const*) const [Engine/Source/Runtime/CoreUObject/Public/UObject/ObjectHandle.h:268] |
| UE-226877 | GitHub 12399 : Reset OpenXRHMD SwapChains declared as static on update |
| UE-229001 | UE 5.5 delayed Python initialization causes issues |
| UE-230070 | [PCG] GPU SM Spawner in loop subgraphs is crashing the editor when added to the viewport |
| UE-228760 | [PCG] GPU - invalid FName values trigger crash |
| UE-229228 | OCIO Crash On Empty Config String |
| UE-230408 | SVG import causes crash due to different file format |
| UE-229953 | [deformer graph] per-bone animation attribute are unusable, they generate shader compilation error when plugged into a kernel |
| UE-228054 | MGPU - QAVirtualProduction crashes at launch |
| UE-223475 | Enabling ZenLoader causes editor crash when undoing Level Instance deletion |
2 Likes
@Amanda.Schade @Matthew.Ivey as I was suspecting 5.5.1 was near to release, I have tried today packaging a project with the 5.5 github branch (AKA 5.5.1) and, when opening the packaged project, it still gives a Fatal Error!
Please!! I’m “seeing” 5.5.1 hotfix is going to be relesed still with this major issue.
PS: using Project Launcher to package.
PS2: UE5 main branch (AKA 5.6) is packaging fine, but not ready for production, of course.
PS3: UE5.3 was packaging finely too. I’m always trying with the same exact project.
Please, I need the coming 5.5.1 being able to package… 
EDIT: Ouch! We were writting at the same time, @Amanda.Schade . I’m going to test that Epic Launcher version and confirm if the error persist 
1 Like
Hi @Amanda.Schade ,
Confirmed, the error is still there… It even fails during packaging if “Don’t include Editor content is marked”. Ridiculous. This is not 5.5p nor 5.5.0; it’s 5.5.1!
Sincerely, I have no enough words, this is a production-ready version, whose main purpose is to be “produced,” and it can’t even do that! Seriously, since the 5.5 preview, haven’t you had time to check this and run packaging tests? But even more: even when LOT of users were complaining about it, just here?
I scheduled my game to be released during December and I was hoping to release it based on 5.5. In the first (5.5p) and second (5.5.0) tries you failed, it’s ok… but with the hotfix again! All I can say is “thank you”.
Sorry if I sound rude, but this is very frustrating. This doesn’t look serious for any business or enterprise, let alone a multi-million-dollar company. I just can’t understand it; it’s like a joke.
PS: Now you can keep ignoring again the rest of the messages (like this one) in this thread. Honestly, I don’t see the point of these “feedback” threads if they’re usually ignored (not to mention the bug reports submitted through the official form). Does Epic Games really not have enough resources to hire more people and compile user feedback thoroughly to pass it on to the development teams? Let’s keep the joke going.
Disappointing and unbelievable.
9 Likes
I guess the fix for the lumen+HWRT dx12 crash didn’t make it into this hotfix. At least there are some workarounds for now.
What a hotfix. World partition HLODs still don’t work.
Perfectly working project in 544 that DID work in 550, albeit with a consistent crash short-time after open (Ultra Dyanamic sky issue/rapid window dragging issue?). Anyways, with the hotfix, this:
becomes this (with no changes, just update/convert):
No lumen, no megalights, no hardware RT, no nanite. Have NOT tried to play w/TAA settings but will try. Grass is the single length-divided-quad using WPO to bend into shape (Ghost of Tsushima grass), not-nanite, otherwise velocities ARE being put-out & it was working as-is before so…:
Performance is slightly-less with the added bonus of the alice-in-wonderland PP-effect… Fun-times.
EDIT: Megalights w/lumen and HWRT turned on crashes (not diagnosing more at this point); 551 just-doesn’t-work for me.
Hey guys!
We highly appreciate the 5.5.1 update! Unfortunately there’s an issue since 5.5 that I haven’t seen any reports on anywhere, which is that HW lumen ignores the Landscape visibility mask. I’ve submitted a bug report upon release, but never actually managed to find it again afterwards.
As seen here, HW lumen with Surface Cache does not factor in any holes in the landscape’s visibility mask.
With SW lumen, this is working fine.
We use visibility masking to hide the landscape over a bunch of nanite meshes and now get diffuse shadows all over the place, as the masked landscape is still “visible” to lumen.
This becomes an even bigger issue with caves, as the landscape would block any diffuse light from falling in. Using Hit Lighting fixes the issue, but the performance cost is too heavy for actual consideration.
In U5.5.1, GetEngineRotationSpeed node might crash with chaosvehicles.
In order to make it easier for you, here you are a very basic packageable project:
https://www.dropbox.com/scl/fi/gsgz3z5p05mgrbaz1y6g4/BUG_packaging_551.zip?rlkey=2b2iqtzi7936vrlrxxbvfb8wt&dl=0
Just try to package as Shipping, in any way you want. After packaging, execute the “game” twice, as the very first time it may open finely, under very specific circumstancies. As a reminder, in 5.6 (main branch) is packaging much better.
PS: I think being able to package is like a maximum-priority thing. Please, could you confirm it is? Just to have any hope.
Thank you very much, if you read this.
I can confirm this happens. I build the provided project as Shipping and after opening the game 5 times it started to give this error :
LowLevelFatalError [File:D:\build++UE5\Sync\Engine\Source\Runtime\D3D12RHI\Private\D3D12Util.cpp] [Line: 991]
RayTracingDevice->CreateStateObject(&Desc, IID_PPV_ARGS(Result.GetInitReference())) failed
at D:\build++UE5\Sync\Engine\Source\Runtime\D3D12RHI\Private\D3D12RayTracing.cpp:663
with error E_INVALIDARG
Crash in runnable thread Background Worker #0
I also tested with my project and it didn’t have any problems, but as soon as I turned the Support Hardware Ray Tracing setting in the project settings it also give me the previous mentioned error
Update : Tested the same build on 2 separate machines one with AMD GPU and one with NVIDIA GPU, same result (if it helps)
Use Source Build if you can or if you had to use from Epic Installer then play in new window(game mode) - something is wrong i had half fps in editor play (installer) . Also Volumetric Cloud takes about 10FPS more than 5.4.4 Video Below
1 Like
Sample project top down example… Who is QCing these builds…
Conclusion to any serious Unreal Engine Dev trying to use world partition and HLOD STAY AWAY from 5.5 & 5.5.1 till this is fixed… I can only assume they broke something with CPU utilization from looking at the comparison of CPU utilization across cores between versions.
5.4.4 HLOD Build times (1 minute and 23 seconds)
5.5.1 HLOD Build times (16 minute and 14 seconds)
4 Likes
Is Niagara Data Channel system working for someone on packed or cooked build with UE5.5.1? Getting no cook issues with it, but there is fatal crash near instantly when writing to data channel. Insight show that completeing but crashes soon after in same frame. Using the islands + the new UE5.5 module method with surface enum condition. No issues in editor, but insta crash in packed game. Cant find error messages in Unreal Insight, it just freezes. Could it be since using GPU particles.
The new material is now more expensive, but you can optimize with performance tips:
Performance and Scalability
1 Like
Any ideas how to fix it?