Procedural Vegetation Nanite Foliage meshes crash packaged project

Milashensky · June 23, 2026, 6:56pm

Summary

Any Static or Skeletal mesh generated through PVE plugin crashes the packaged game in ue5.8. This includes assets packaged with the plugin itself as well as Megaplants. Meshes are rendered and run in the editor with no problems, but in the packaged project cause the crash once loaded. Disabling nanite on the mesh resolves the crash (but doesn’t renders the mesh properly).
Works fine in ue5.7.4.

What Type of Bug are you experiencing?

Foundation (C++ Tools, Profiling, & Pipeline)

Steps to Reproduce

Start a new 3rd person template project in ue5.8, Target Platform: Desktop; Quality: Any, Variant: None
Go to Project settings
Enable Nanite Foliage
Go to plugins
Enable Procedural Vegetation Editor plugin
Restart
Place any PVE generated mesh (static or skeletal) in the starter world. Easiest way is to use:
/ProceduralVegetationEditor/SampleAssets/StarterContent/DeciduousTree_01/PVE_Deciduous_Tree_01
Save
Package the project for Windows
Run the packaged Project

Expected Result

Packaged game starts and mesh is observed in the level

Observed Result

Packaged game starts but crashes during the asset load. Crash report window is not shown.

Affects Versions

5.8

Platform(s)

Windows

For crash reports, include your callstack

from \Saved\Logs

[2026.06.23-17.27.08:437][  0]LogWindows: Error: === Critical error: ===
[2026.06.23-17.27.08:437][  0]LogWindows: Error: 
[2026.06.23-17.27.08:437][  0]LogWindows: Error: Assertion failed: At >= 0 && At < (uint32)IndexStorage.Num() [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Public\RawIndexBuffer.h] [Line: 198] 
[2026.06.23-17.27.08:437][  0]LogWindows: Error: 
[2026.06.23-17.27.08:437][  0]LogWindows: Error: 
[2026.06.23-17.27.08:437][  0]LogWindows: Error: 
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff766eba2d8 TestPVE2.exe!FDebug::CheckVerifyFailedImpl2() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff7734e960f TestPVE2.exe!FPVLightDetection::BuildLeafMeshGeometry() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76781794d TestPVE2.exe!UObject::ConditionalPostLoad() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff767aa428a TestPVE2.exe!FAsyncPackage2::Event_DeferredPostLoad() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff767aa6a00 TestPVE2.exe!FEventLoadNode2::Execute() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff767aa7dca TestPVE2.exe!FAsyncLoadEventQueue2::ExecuteSyncLoadEvents() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff767abd019 TestPVE2.exe!FAsyncLoadingThread2::ProcessLoadedPackagesFromGameThread() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff767aca819 TestPVE2.exe!FAsyncLoadingThread2::TickAsyncLoadingFromGameThread() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff767aa9e6d TestPVE2.exe!FAsyncLoadingThread2::FlushLoading() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff767637959 TestPVE2.exe!FlushAsyncLoading() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76763756c TestPVE2.exe!FlushAsyncLoading() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff7679da240 TestPVE2.exe!LoadPackageInternal() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff7679d97ef TestPVE2.exe!LoadPackage() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff7679d9b2e TestPVE2.exe!LoadPackage() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76bb93c05 TestPVE2.exe!UEngine::LoadMap() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76bb554af TestPVE2.exe!UEngine::Browse() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76ab6c389 TestPVE2.exe!UGameInstance::StartGameInstance() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76aaeceab TestPVE2.exe!UGameEngine::Start() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76edfe8e3 TestPVE2.exe!FEngineLoop::Init() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76edfdcf7 TestPVE2.exe!GuardedMain() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76edfdeba TestPVE2.exe!GuardedMainWrapper() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76ee01aa0 TestPVE2.exe!LaunchWindowsStartup() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff76ee10894 TestPVE2.exe!WinMain() []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ff774a4567e TestPVE2.exe!__scrt_common_main_seh() [D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
[2026.06.23-17.27.08:437][  0]LogWindows: Error: [Callstack] 0x00007ffaec7fe957 KERNEL32.DLL!UnknownFunction []
[2026.06.23-17.27.08:437][  0]LogWindows: Error: 
[2026.06.23-17.27.08:439][  0]LogExit: Executing StaticShutdownAfterError
[2026.06.23-17.27.08:441][  0]LogWindows: FPlatformMisc::RequestExit(1, LaunchWindowsStartup.ExceptionHandler)
[2026.06.23-17.27.08:441][  0]LogWindows: FPlatformMisc::RequestExitWithStatus(1, 3, LaunchWindowsStartup.ExceptionHandler)
[2026.06.23-17.27.08:441][  0]LogCore: Engine exit requested (reason: Win RequestExit)

tomaszrozynski · June 24, 2026, 7:48pm

Hey. I’m getting the exact same error when using Nanite Foliage. The build development crashes while loading the level. 5.8

ObjOri · June 26, 2026, 2:22pm

EPIC: BE ADVISED (ISSUE ISOLATED)

I have precisely the same problem.

I spent yesterday testing every possible PVE mesh inclusion and subsequent game packaging scenario, as well as “all” known fixes (to include a baker’s dozen of my own), as sometimes (usually close to creation or upon creation and first placement of a new PVE export skeletal mesh), the package is good and playable. But, the occurrence of a “good” packaging is more likely random with lousy odds.

OCCURRENCE TEST SCENARIO

Once I realized the issue was discretely PVE mesh-related (exporting to static mesh and opening the static mesh to CPU are NOT fixes), I tested the likelihood of occurrence.

As I was able to launch a fresh-project game with three instances of a skeletal mesh tree in-scene, I then placed each tree in its own sublevel. I then packaged the game to three empty, numbered folders and checked the game logs of those that crashed.

FINDINGS

All crashed! But they did so in different sublevels.

I then repeated the test three times, and never had another success. But, the game crashed, covering every combination of sublevel, in which the asset had crashed.

This means that the problem is random with a low likelihood of success after first placement of a newly exported PVE mesh. And it’s always the same proceeding “198” line in the log:

LogLoad: LoadMap: /Game/FirstPerson/Lvl_FirstPerson?Name=Player
Assertion failed: At >= 0 && At < (uint32)IndexStorage.Num() [File:D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Public\RawIndexBuffer.h] [Line: 198]

-- followed by:

Assertion failed: At >= 0 && At < (uint32)IndexStorage.Num() [File:D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Public\RawIndexBuffer.h] [Line: 198]

IMPORTANT NOTE AND CAVEATS

The specific sublevel that did not load preceded the lines above in every case, failing there in the loading of that sublevels mesh.

I loaded levels in the same sequence, every time. Thus, if the first or second sublevel crashed the game, the viability of cascading meshes is unknown.

Also, the issue may be, specifically, related to the mesh’s nanite foliage.

------------

Andrea_92 · June 30, 2026, 9:34am

I also had the same problem after converting from 5.7 to 5.8 I had this crash after packaging the project in shipping

Flak · July 2, 2026, 1:13pm

Don’t forget to vote if this is happening to you. At 5 votes, a ticket will be created.

Flak · July 2, 2026, 1:13pm

You can also vote for your own post

Donalf · July 5, 2026, 12:14pm

Confirming this on UE 5.8.

Clean packaged build with any megaplants crashes on launch.
Re-exporting skeletal meshes from the PVE asset does not resolve the issue.
Project packages successfully; crash only occurs when the packaged executable starts.

I can reproduce this consistently.

AerixArtGames · July 22, 2026, 7:51pm

Been receiving this crash on packaged shipping builds as well. No solutions yet on this.

Andrea_92 · July 29, 2026, 8:25am

In version 5.8.1 it seems to work in my case

Bug-Reporter · July 30, 2026, 9:00am

UE-386321 is ‘Closed’ as ‘Fixed’.

Donalf · August 1, 2026, 4:18pm

Still not working - I created a clean 5.8.1 first person project, added Dynamic Wind and Procedural Vegetation Editor plugins, packaged an Asset Zoo map, and it does not launch.

Andrea_92 · August 2, 2026, 3:22pm

I used my own project. I think the problem is with the trees created with an older version of Engine 5.7 or Nanite Foliage. When I opened my project with 5.8.1 and opened the tree’s skeletal mesh, it no longer had a skeleton. I deleted the old trees from my project and added the PVE_Conifer_01 trees found in Engine/Plugins/ProceduralVegetionEditorContent. This works for me both in the editor and in build shipping.

Andrea_Buttarini · August 6, 2026, 7:41pm

(post deleted by author)

Andrea_Buttarini · August 6, 2026, 9:20pm

I tried everything, but the bug is still present in my 5.8.1 project. Procedural Vegetation works in the Editor, but not in packaged projects (Development and Shipping). I also re-downloaded all the Quixel Megaplants for 5.8.1 and removed old references. Can anyone else confirm the presence of this bug in 5.8.1?

Andrea_92 · August 6, 2026, 9:54pm

You can try to use trees as I wrote in my previous message?

Andrea_Buttarini · August 6, 2026, 11:39pm

(post deleted by author)

Andrea_Buttarini · August 6, 2026, 11:40pm

When you say “In version 5.8.1 it seems to work in my case”, you mean you tried with Megaplants downloaded from FAB or with the PVE_Conifer_01 trees found in the plugin folder? Because the point is it has to work with stuff we download from FAB.

Donalf · August 7, 2026, 9:53am

Yes, I’m still running into the same issue in 5.8.1 - new clean project, procedural vegetation and megaplants work in editor, but packaged builds fail to launch.

Andrea_Buttarini · August 7, 2026, 1:13pm

Thanks @Donalf. The weird thing is that when I converted my project, which already had procedural vegetation and megaplants, from 5.7 to 5.8, I was able to package and run it properly in 5.8. However, when I downloaded the 5.8 megaplants to overwrite the old ones, I started having the issue described above. If someone else confirms the issue is still there, we should open a ticket.

futurecreep · August 7, 2026, 4:08pm

Can also confirm the issue is present in 5.8.1, however if you check the “Fixed” dropdown here it says target fix: 5.8.2
You can also find the actual fix commit in the dev branch but not the release one yet (so it’s on the way) https://github.com/EpicGames/UnrealEngine/commit/3b641028fab5389fca14af9b4bff5d4dd711b729 (You need access to see this)

If it can’t wait until 5.8.2 pull just the dev-5.8 version of the PVE plugin and keep it in your project folder (and move out the one in the engine files). Can confirm it works at least with some quick testing.