This is an infrequent but trending crash coming out of the 4.18 release. Users have not provided any descriptions of their actions when the crash occurred.
The last "User Activity" on all crashes references: Layout="Sequencer" Label="Sequencer" Content=SNullWidgetContent
Update: some newer crashes are outside of Sequencer (SGraphEditor, STutorialsBrowser)
Source Context
1388 // Draw all windows
1389 for (const TSharedRef<SWindow>& CurrentWindow : SlateWindows)
1390 {
1391 PrepassWindowAndChildren(CurrentWindow);
1392 }
1393 }
1394 }
1395
1396
1397 TArray<TSharedRef<SWindow>> GatherAllDescendants(const TArray< TSharedRef<SWindow> >& InWindowList)
1398 {
1399 ***** TArray<TSharedRef<SWindow>> GatheredDescendants(InWindowList);
1400
1401 for (const TSharedRef<SWindow>& SomeWindow : InWindowList)
1402 {
1403 GatheredDescendants.Append( GatherAllDescendants( SomeWindow->GetChildWindows() ) );
1404 }
1405
1406 return GatheredDescendants;
1407 }
repro steps currently unknown
Access violation - code c0000005 (first/second chance not available) UE4Editor_Slate!GatherAllDescendants() [slateapplication.cpp:1400] UE4Editor_Slate!GatherAllDescendants() [slateapplication.cpp:1404] UE4Editor_Slate!FSlateApplication::PrivateDrawWindows() [slateapplication.cpp:1484] UE4Editor_Slate!FSlateApplication::DrawWindows() [slateapplication.cpp:1190] UE4Editor_Slate!FSlateApplication::TickApplication() [slateapplication.cpp:1777] UE4Editor_Slate!FSlateApplication::Tick() [slateapplication.cpp:1595] UE4Editor!FEngineLoop::Tick() [launchengineloop.cpp:3378] UE4Editor!GuardedMain() [launch.cpp:166] UE4Editor!GuardedMainWrapper() [launchwindows.cpp:134] UE4Editor!WinMain() [launchwindows.cpp:210] UE4Editor!__scrt_common_main_seh() [exe_common.inl:253] kernel32!BaseThreadInitThunk() ntdll!RtlUserThreadStart()
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-52283 in the post.