This crash was reported on the UDN. Upon further investigation it has been experienced by a handful of different users throughout 4.11 and 4.12. JIRA logged for tracking despite unknown repro steps at the time.
A similar callstack also occurred through 4.9 and 4.10: [Link Removed]
User Description(s)
Repro steps currently unknown. Related to Vertex Painting
Game.log Fatal error: [File:D:\BuildAgent\work\223cc57df4eefd54\------\ue4\Engine\Source\Runtime\CoreUObject\Private\Templates\Casts.cpp] [Line: 11] Cast of nullptr to Actor failed UE4Editor_CoreUObject!CastLogError() [casts.cpp:12] UE4Editor_MeshPaint!CastChecked<AActor,UObject>() [casts.h:203] UE4Editor_MeshPaint!SMeshPaint::IsPushInstanceVertexColorsToMeshButtonEnabled() [smeshpaint.cpp:2459] UE4Editor_MeshPaint!TBaseSPMethodDelegateInstance<1,SMeshPaint,0,bool __cdecl() [delegateinstancesimpl_variadics.inl:321] UE4Editor_SlateCore!TAttribute<bool>::Get() [attribute.h:135] UE4Editor_SlateCore!SWidget::ShouldBeEnabled() [swidget.h:987] UE4Editor_Slate!SButton::OnPaint() [sbutton.cpp:73] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SCompoundWidget::OnPaint() [scompoundwidget.cpp:25] UE4Editor_Slate!SBorder::OnPaint() [sborder.cpp:90] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SOverlay::OnPaint() [soverlay.cpp:100] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SCompoundWidget::OnPaint() [scompoundwidget.cpp:25] UE4Editor_Slate!SScrollBox::OnPaint() [sscrollbox.cpp:922] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SCompoundWidget::OnPaint() [scompoundwidget.cpp:25] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SCompoundWidget::OnPaint() [scompoundwidget.cpp:25] UE4Editor_Slate!SBorder::OnPaint() [sborder.cpp:90] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SCompoundWidget::OnPaint() [scompoundwidget.cpp:25] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_Slate!SBox::OnPaint() [sbox.cpp:171] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SCompoundWidget::OnPaint() [scompoundwidget.cpp:25] UE4Editor_Slate!SBorder::OnPaint() [sborder.cpp:90] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SOverlay::OnPaint() [soverlay.cpp:100] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_SlateCore!SPanel::OnPaint() [spanel.cpp:19] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SCompoundWidget::OnPaint() [scompoundwidget.cpp:25] UE4Editor_SlateCore!SWidget::Paint() [swidget.cpp:669] UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [spanel.cpp:44] UE4Editor_Slate!SSplitter::OnPaint() [ssplitter.cpp:166]
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