This is an infrequent Mac crash in the 4.18 release. The callstack is similar to [Link Removed] and originally thought to be part of the same issue, but that Jira has been fixed and many other similar callstacks have stopped occurring in 4.18.1, while this one still continues.
User Descriptions
Callstack from Log
[2017.11.21-10.52.31:844][373]LogBlueprintUserMessages: Late EndPlayMap Detection: Level '/Game/***/Maps/TopDownExampleMap.TopDownExampleMap:PersistentLevel' has LevelScriptBlueprint '/Game/***/Maps/TopDownExampleMap.TopDownExampleMap:PersistentLevel.TopDownExampleMap' with GeneratedClass '/Game/***/Maps/TopDownExampleMap.TopDownExampleMap_C' with ClassGeneratedBy '/Game/***/Maps/TopDownExampleMap.TopDownExampleMap:PersistentLevel.TopDownExampleMap' [2017.11.21-10.52.35:727][505]LogMac: === Critical error: === SIGSEGV: invalid attempt to access memory at address 0x10c [2017.11.21-10.52.35:727][505]LogMac: 0x1155af5a UE4Editor-ApplicationCore.dylib!FMacWindow::ApplySizeAndModeChanges(int, int, int, int, EWindowMode::Type) [UnknownFile]) 0x12085c91 UE4Editor-SlateCore.dylib!SWindow::Resize(FVector2D) [UnknownFile]) 0x1160ac71 UE4Editor-Slate.dylib!PrepassWindowAndChildren(TSharedRef<SWindow, (ESPMode)0>) [UnknownFile]) 0x1160adf1 UE4Editor-Slate.dylib!PrepassWindowAndChildren(TSharedRef<SWindow, (ESPMode)0>) [UnknownFile]) 0x1160a11c UE4Editor-Slate.dylib!FSlateApplication::DrawPrepass(TSharedPtr<SWindow, (ESPMode)0>) [UnknownFile]) 0x1160662d UE4Editor-Slate.dylib!FSlateApplication::PrivateDrawWindows(TSharedPtr<SWindow, (ESPMode)0>) [UnknownFile]) 0x11606132 UE4Editor-Slate.dylib!FSlateApplication::DrawWindows() [UnknownFile]) 0x1160f2ed UE4Editor-Slate.dylib!FSlateApplication::TickApplication(ESlateTickType, float) [UnknownFile]) 0x1160d296 UE4Editor-Slate.dylib!FSlateApplication::Tick(ESlateTickType) [UnknownFile]) 0x0b57c8de UE4Editor!FEngineLoop::Tick() [UnknownFile]) 0x0b5847a2 UE4Editor!GuardedMain(wchar_t const*) [UnknownFile]) 0x0b591e40 UE4Editor!-[UE4AppDelegate runGameThread:] [UnknownFile]) 0x0c47ad17 UE4Editor-Core.dylib!-[FCocoaGameThread main] [UnknownFile]) 0x3573b6d8 Foundation!__NSThread__start__() [UnknownFile]) 0x5aee96c1 libsystem_pthread.dylib!_pthread_body() [UnknownFile]) 0x5aee956d libsystem_pthread.dylib!_pthread_body() [UnknownFile]) 0x5aee8c5d libsystem_pthread.dylib!thread_start() [UnknownFile])
repro steps currently unknown
SEGV_MAPERR at 0x10c UE4Editor-ApplicationCore.dylib!FMacWindow::ApplySizeAndModeChanges() UE4Editor-SlateCore.dylib!SWindow::Resize() UE4Editor-Slate.dylib!PrepassWindowAndChildren(TSharedRef<SWindow,() UE4Editor-Slate.dylib!PrepassWindowAndChildren(TSharedRef<SWindow,() UE4Editor-Slate.dylib!FSlateApplication::DrawPrepass(TSharedPtr<SWindow,() UE4Editor-Slate.dylib!FSlateApplication::PrivateDrawWindows(TSharedPtr<SWindow,() UE4Editor-Slate.dylib!FSlateApplication::DrawWindows() UE4Editor-Slate.dylib!FSlateApplication::TickApplication() UE4Editor-Slate.dylib!FSlateApplication::Tick() UE4Editor!FEngineLoop::Tick() UE4Editor!GuardedMain() UE4Editor!<Unknown> UE4Editor-Core.dylib!<Unknown> Foundation!Unknown() libsystem_pthread.dylib!<Unknown> libsystem_pthread.dylib!<Unknown> libsystem_pthread.dylib!<Unknown>
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-52644 in the post.