5.1.1 project won't open

Development Programming & Scripting C++
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1

Cannot open project with latest 5.1.1 while ExternalObjects and ExternalActors exists in Content folder due to:
assertion failed: (Index >= 0) & (Index < ArrayNum)
and
UnrealEditor-Niagara.pdb not loaded

one of my actors has a Niagara System attached to it and the map doesn’t seem to open.

What do I have to do to get it to load again?

here’s the end part of log:


0]LogWorldPartition: Display: WorldPartition initialize started...
[2023.02.08-10.23.33:241][  0]LogWorldPartition: UWorldPartition::Initialize(Asset=ThirdPersonMap, IsEditor=1, bPIEWorldTravel=0 IsGame=0, IsCooking=0)
[2023.02.08-10.23.33:335][  0]LogOutputDevice: Warning: 

Script Stack (0 frames) :

[2023.02.08-10.23.33:347][  0]LogWindows: Error: appError called: Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 763] 
Array index out of bounds: 1 from an array of size 1

[2023.02.08-10.23.33:347][  0]LogWindows: Windows GetLastError: The operation completed successfully. (0)

The project was working fine previously and it doesn’t have any C++ code related to Niagara, however it did some Niagara systems placed on the map. I’ve tried to clone it from a working source and rebuild it, but nothing changes. I’m not sure what the 5.1.1 changed or if I have to rebuild it somehow differently.

2

Quite the same problem bro. My project started crashing everytime I open it. Does anyone know how to get back to 5.1?

3

My dirty fix so far was to Move ExternalActors and ExternalObjects out of the content folder, open the editor, and start moving them back in until it crashed.

Found the .uasset that was causing the error in the map. No idea where the error comes from.
I consisted of a Timeline that was not connected, skeletal mesh with a sword attached to a socket and a particle system attached to the sword. And an animation asset that looped.
Pretty much a standard actor for testing purposes. The Niagara System has a StaticMesh DataInterface

Edit: A little bit less dirty fix. I was using Source Control, and I think Niagara default user parameters that didn’t exist any longer in the FX, but did in the blueprint somehow corrupted it. That’s my guess.

Had to revert last 3 changes and create a new branch for 5.1.1. However the first method did help me to find where to look.