Summary
Audio Insights crashes immediately upon opening the Audio Insights window in Unreal Engine 5.6.1 on macOS. The crash is 100% reproducible across all projects, including brand-new blank Blueprint projects.
The assertion occurs while registering the Audio Insights Slate style:
Assertion failed: !FindSlateStyle(SlateStyleName)
File: Runtime/SlateCore/Private/Styling/SlateStyleRegistry.cpp
Line: 21
The crash occurs before any Audio Insights UI is displayed.
What Type of Bug are you experiencing?
Audio
Steps to Reproduce
Launch Unreal Engine 5.6.1.
Create a brand-new Blank Blueprint project.
Enable the Audio Insights plugin.
Restart the editor.
Select:
Tools
→ Audio Insights
The editor immediately crashes before the Audio Insights window appears.
Expected Result
The Audio Insights window opens normally.
Observed Result
The editor crashes immediately with:
Assertion failed: !FindSlateStyle(SlateStyleName)
Affects Versions
5.6
Platform(s)
Mac
For crash reports, include your callstack
Assertion failed: !FindSlateStyle(SlateStyleName) [File:./Runtime/SlateCore/Private/Styling/SlateStyleRegistry.cpp] [Line: 21]
0x0802d430 UnrealEditor-Core.dylib!FGenericPlatformMisc::RaiseException(unsigned int)
0x08381930 UnrealEditor-Core.dylib!FOutputDevice::LogfImpl(char16_t const*, …)
0x08273078 UnrealEditor-Core.dylib!FDebug::CheckVerifyFailedImpl2V(char const*, char const*, int, char16_t const*, char*)
0x0826e8f4 UnrealEditor-Core.dylib!FDebug::CheckVerifyFailedImpl2(char const*, char const*, int, char16_t const*, …)
0x0634955c UnrealEditor-SlateCore.dylib!FSlateStyleRegistry::RegisterSlateStyle(ISlateStyle const&)
0x7897dc28 UnrealEditor-AudioInsights.dylib!UE::Audio::Insights::FSlateStyle::FSlateStyle()
0x78913250 UnrealEditor-AudioInsights.dylib!UE::Audio::Insights::FLogDashboardViewFactory::GetIcon() const
0x77b6b4a4 UnrealEditor-AudioInsightsEditor.dylib!UE::Audio::Insights::FEditorDashboardFactory::RegisterTabSpawners()
0x77b69788 UnrealEditor-AudioInsightsEditor.dylib!UE::Audio::Insights::FEditorDashboardFactory::MakeDockTabWidget(FSpawnTabArgs const&)
0x050c7228 UnrealEditor-Slate.dylib!FTabManager::SpawnTab(FTabId const&, TSharedPtr<SWindow, (ESPMode)1> const&, bool)
0x050cb5f0 UnrealEditor-Slate.dylib!FTabManager::RestoreArea_Helper(TSharedRef<FTabManager::FLayoutNode, (ESPMode)1> const&, TSharedPtr<SWindow, (ESPMode)1> const&, bool, FSidebarTabLists&, EOutputCanBeNullptr, bool)
0x050cfab4 UnrealEditor-Slate.dylib!FTabManager::RestoreSplitterContent(TSharedRef<FTabManager::FSplitter, (ESPMode)1> const&, TSharedRef<SDockingSplitter, (ESPMode)1> const&, TSharedPtr<SWindow, (ESPMode)1> const&, FSidebarTabLists&)
0x050cd1a0 UnrealEditor-Slate.dylib!FTabManager::RestoreArea_Helper(TSharedRef<FTabManager::FLayoutNode, (ESPMode)1> const&, TSharedPtr<SWindow, (ESPMode)1> const&, bool, FSidebarTabLists&, EOutputCanBeNullptr, bool)
0x050c140c UnrealEditor-Slate.dylib!FTabManager::RestoreArea(TSharedRef<FTabManager::FArea, (ESPMode)1> const&, TSharedPtr<SWindow, (ESPMode)1> const&, bool, EOutputCanBeNullptr, bool)
0x050c579c UnrealEditor-Slate.dylib!FTabManager::InvokeTab_Internal(FTabId const&, bool, bool)
0x050c55c8 UnrealEditor-Slate.dylib!FTabManager::InvokeTab_Internal(FTabId const&, bool, bool)
0x050c4db4 UnrealEditor-Slate.dylib!FTabManager::TryInvokeTab(FTabId const&, bool)
0x050c95ac UnrealEditor-Slate.dylib!FTabManager::InvokeTabForMenu(FName)
0x05135b24 UnrealEditor-Slate.dylib!TBaseSPMethodDelegateInstance<false, FTabManager, (ESPMode)1, void (), FDefaultDelegateUserPolicy, FName>::ExecuteIfSafe() const
0x0519501c UnrealEditor-Slate.dylib!SMenuEntryBlock::OnClicked(bool)
0x051867e0 UnrealEditor-Slate.dylib!SMenuEntryBlock::OnMenuItemButtonClicked()
0x05213bac UnrealEditor-Slate.dylib!TBaseSPMethodDelegateInstance<false, SMenuEntryBlock, (ESPMode)1, FReply (), FDefaultDelegateUserPolicy>::Execute() const
0x0526f7b4 UnrealEditor-Slate.dylib!SButton::ExecuteOnClick()
0x0528c724 UnrealEditor-Slate.dylib!SButton::OnMouseButtonUp(FGeometry const&, FPointerEvent const&)
0x0500607c UnrealEditor-Slate.dylib!FSlateApplication::RoutePointerUpEvent(FWidgetPath const&, FPointerEvent const&)
0x04fc4f1c UnrealEditor-Slate.dylib!FSlateApplication::ProcessMouseButtonUpEvent(FPointerEvent const&)
0x0500ba64 UnrealEditor-Slate.dylib!FSlateApplication::OnMouseUp(EMouseButtons::Type, UE::Math::TVector2)
0x04d7b110 UnrealEditor-ApplicationCore.dylib!FMacApplication::ProcessMouseUpEvent(FDeferredMacEvent const&, TSharedPtr<FMacWindow, (ESPMode)1>)
0x04d75974 UnrealEditor-ApplicationCore.dylib!FMacApplication::ProcessEvent(FDeferredMacEvent const&)
0x04d755bc UnrealEditor-ApplicationCore.dylib!FMacApplication::ProcessDeferredEvents(float)
0x04fe2518 UnrealEditor-Slate.dylib!FSlateApplication::TickPlatform(float)
0x04fe1a88 UnrealEditor-Slate.dylib!FSlateApplication::Tick(ESlateTickType)
0x0454c0fc UnrealEditor!FEngineLoop::Tick()
0x04554614 UnrealEditor!GuardedMain(char16_t const*)
0x0456e400 UnrealEditor!-[UEAppDelegate runGameThread:]
0x081e7b4c UnrealEditor-Core.dylib!-[FCocoaGameThread main]
0x9967aba8 Foundation!NSThread__start()
0x97fc7c0c libsystem_pthread.dylib!_pthread_start()
0x97fc2b80 libsystem_pthread.dylib!thread_start()
Additional Notes
Additional investigation: I reproduced this in a brand-new Blank Blueprint project with only the Audio Insights plugin enabled. I verified the engine installation, deleted project caches/configuration, and inspected AudioInsightsStyle.h. The crash occurs during FSlateStyleRegistry::RegisterSlateStyle(*this) inside UE::Audio::Insights::FSlateStyle, suggesting a duplicate Slate style registration before the Audio Insights window is created.