Unreal Engine Issues
Unreal Engine Issues
Niagara crash when using a particle attribute reader that has been passed around between modules
UE - Niagara - Oct 28, 2025The following Niagara usage pattern results in either a crash or in incorrect data being read from a Particle Attribute Reader: Emitter Spawn Stage – A module has an Attribute Reader input specifie ...
Intermittent Content is Missing from Cook errors for objects with Niagara packages
UE - Niagara - Oct 15, 2025Intermittently when cooking large licensee projects, an error is reported at the end of the cook:LogCook: Error: Content is missing from cook. Source package referenced an object in target package b ...
Heterogeneous Volume Actor causes ensures to trigger in Debug builds
UE - Niagara - Aug 24, 2025When a heterogeneous volume actor is used with a volume material in a debug build, the following ensures are triggered: Ensure condition failed: UniformBufferValue || EnumHasAnyFlags(AutomaticallyBo ...
Niagara Data Interface "Errors and Warning" section on Module Details not updating when error messages change
UE - Niagara - Aug 14, 2025This is a regression: it worked correctly up to UE 5.5, but not in 5.6 or mainline latest. Possibly caused by CL 40093049. Class UNiagaraDataInterface provides virtual method GetFeedback(), which a ...
Vector VM - Crash / memory stomp when using > 255 external function calls
UE - Niagara - Aug 12, 2025The Vector VM has only every supported a byte's worth of external function calls, when we blew the limit it would index into the incorrect VM call. The new VM will also overwrite memory when exceed ...
FNiagaraStackGraphUtilities::FindScriptModulesInStack() parameter "OutFunctionCalls" should be a reference
UE - Niagara - Aug 11, 2025On file [Engine\Plugins\FX\Niagara\Source\NiagaraEditor\Public\ViewModels\Stack\NiagaraStackGraphUtilities.h], function FNiagaraStackGraphUtilities::FindScriptModulesInStack() receives a parameter " ...
Niagara Regression - Looping particle with Spawn Burst Instantaneous on time 0.0 flickers for a frame between loops
UE - Niagara - Jul 16, 2025Note: This worked correctly up to UE 5.4, but repros from UE 5.5 up to mainline latest. If a Niagara Emitter is set up with "Spawn Burst Instantaneous" on time 0.0, and the spawned particle(s) have ...
Editor crash when adding mesh renderer elements in Niagara
UE - Niagara - Jul 8, 2025When adding multiple meshes to a Niagara Mesh Renderer Module, a check() will be triggered due to a mismatch in the number of Widgets and the number of Tooltip Widgets. ...
Incorrect NiagaraSystem passed to KillUnusedComponents in ReclaimWorldParticleSystem
UE - Niagara - Jun 10, 2025In UNiagaraComponentPool::ReclaimWorldParticleSystem, the cleanup loop for WorldParticleSystemPools calls KillUnusedComponents with the reclaimed component's NiagaraSystem (Asset) instead of the sys ...
Niagara Scalability Crash When Processing Significance
UE - Niagara - Jun 4, 2025Method FNiagaraScalabilityManager::ProcessSignificance() iterates on indices from Context.SignificanceIndices and uses them to access the State and ManagedComponents arrays. It can then decide to cr ...