[Crash] Exiting PIE after a travel

In 4.8.1, while testing our game in PIE, if we reload the map after a death using AGameMode::RestartGame(), the editor will crash every time with this callstack.

>	UE4Editor-Core.dll!FOutputDeviceWindowsError::Serialize(const wchar_t * Msg, ELogVerbosity::Type Verbosity, const FName & Category) Line 68	C++
 	UE4Editor-Core.dll!FOutputDevice::Logf__VA(const wchar_t * Fmt, ...) Line 144	C++
 	UE4Editor-Core.dll!FDebug::AssertFailed(const char * Expr, const char * File, int Line, const wchar_t * Format, ...) Line 355	C++
 	UE4Editor-Core.dll!FMsg::Logf__VA(const char * File, int Line, const FName & Category, ELogVerbosity::Type Verbosity, const wchar_t * Fmt, ...) Line 523	C++
 	UE4Editor-MessageLog.dll!FMessageLogListingModel::AddMessageInternal(const TSharedRef<FTokenizedMessage,0> & NewMessage) Line 70	C++
 	UE4Editor-MessageLog.dll!FMessageLogListingModel::AddMessages(const TArray<TSharedRef<FTokenizedMessage,0>,FDefaultAllocator> & NewMessages) Line 89	C++
 	UE4Editor-Core.dll!FMessageLog::Flush() Line 188	C++
 	UE4Editor-Core.dll!FMessageLog::~FMessageLog() Line 91	C++
 	UE4Editor-UnrealEd.dll!UEditorEngine::EndPlayMap() Line 289	C++
 	UE4Editor-UnrealEd.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 973	C++
 	UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 366	C++
 	UE4Editor.exe!FEngineLoop::Tick() Line 2359	C++
 	UE4Editor.exe!GuardedMain(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 142	C++
 	UE4Editor.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 189	C++
 	[External Code]	

and this output

[2015.06.26-20.37.32:970][727]LogReferenceChain: Searching referencers for Level1_Layout. This may take several minutes.
[2015.06.26-20.37.33:078][727]LogReferenceChain: Generating reference graph ...
[2015.06.26-20.37.33:086][727]LogReferenceChain: Level 0 has 10 nodes ...
[2015.06.26-20.37.33:097][727]LogReferenceChain: Level 1 added 210 nodes ...
[2015.06.26-20.37.33:109][727]LogReferenceChain: Level 2 added 1438 nodes ...
[2015.06.26-20.37.33:124][727]LogReferenceChain: Level 3 added 4501 nodes ...
[2015.06.26-20.37.33:141][727]LogReferenceChain: Level 4 added 13671 nodes ...
[2015.06.26-20.37.33:153][727]LogReferenceChain: Level 5 added 4420 nodes ...
[2015.06.26-20.37.33:161][727]LogReferenceChain: Level 6 added 0 nodes ...
[2015.06.26-20.37.33:162][727]LogReferenceChain: Generating reference chains ...
[2015.06.26-20.37.33:163][727]LogReferenceChain:   
[2015.06.26-20.37.33:163][727]LogReferenceChain: External Referencers:
[2015.06.26-20.37.33:163][727]LogReferenceChain:   
[2015.06.26-20.37.37:261][727]LogReferenceChain: (root) UnrealEdEngine /Engine/Transient.UnrealEdEngine_0->UE4Editor-UnrealEd.dll!UEditorEngine::AddReferencedObjects() {0x00007ff80c88d3f0} + 0 bytes [d:\lag\bump\project\master\engine\source\editor\unrealed\priv
[2015.06.26-20.37.37:262][727]LogReferenceChain:   (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
[2015.06.26-20.37.37:262][727]LogReferenceChain:   
[2015.06.26-20.37.37:263][727]LogReferenceChain: Internal Referencers:
[2015.06.26-20.37.37:263][727]LogReferenceChain:   
[2015.06.26-20.37.37:263][727]LogReferenceChain: (root) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout->CurrentLevel
[2015.06.26-20.37.37:263][727]LogReferenceChain:   Level /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:PersistentLevel->OwningWorld
[2015.06.26-20.37.37:263][727]LogReferenceChain:     (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
[2015.06.26-20.37.37:264][727]LogReferenceChain:   
[2015.06.26-20.37.37:264][727]LogReferenceChain: (root) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout->NavigationSystem
[2015.06.26-20.37.37:264][727]LogReferenceChain:   NavigationSystem /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:NavigationSystem_1->Outer
[2015.06.26-20.37.37:264][727]LogReferenceChain:     (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
[2015.06.26-20.37.37:264][727]LogReferenceChain:   
[2015.06.26-20.37.37:264][727]LogReferenceChain: (root) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout->AvoidanceManager
[2015.06.26-20.37.37:265][727]LogReferenceChain:   AvoidanceManager /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:AvoidanceManager_1->Outer
[2015.06.26-20.37.37:265][727]LogReferenceChain:     (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
[2015.06.26-20.37.37:265][727]LogReferenceChain:   
[2015.06.26-20.37.37:265][727]LogReferenceChain: (root) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout->ThumbnailInfo
[2015.06.26-20.37.37:265][727]LogReferenceChain:   WorldThumbnailInfo /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:WorldThumbnailInfo_0->Outer
[2015.06.26-20.37.37:265][727]LogReferenceChain:     (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
[2015.06.26-20.37.37:265][727]LogReferenceChain:   
[2015.06.26-20.37.37:266][727]LogReferenceChain: (root) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout->PhysicsCollisionHandler
[2015.06.26-20.37.37:266][727]LogReferenceChain:   PhysicsCollisionHandler /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:PhysicsCollisionHandler_1->Outer
[2015.06.26-20.37.37:266][727]LogReferenceChain:     (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
[2015.06.26-20.37.37:266][727]LogReferenceChain:   
[2015.06.26-20.37.37:266][727]LogReferenceChain: (root) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout->AISystem
[2015.06.26-20.37.37:266][727]LogReferenceChain:   AISystem /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:AISystem_1->Outer
[2015.06.26-20.37.37:267][727]LogReferenceChain:     (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
[2015.06.26-20.37.37:267][727]LogReferenceChain:   
[2015.06.26-20.37.37:267][727]LogReferenceChain: (root) CrowdManager /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:NavigationSystem_1.CrowdManager_0->Outer
[2015.06.26-20.37.37:267][727]LogReferenceChain:   NavigationSystem /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:NavigationSystem_1->Outer
[2015.06.26-20.37.37:267][727]LogReferenceChain:     (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
[2015.06.26-20.37.37:267][727]LogReferenceChain:   
[2015.06.26-20.37.37:267][727]LogReferenceChain: (root) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout->DefaultPhysicsVolume
[2015.06.26-20.37.37:268][727]LogReferenceChain:   DefaultPhysicsVolume /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:PersistentLevel.DefaultPhysicsVolume_1->Outer
[2015.06.26-20.37.37:268][727]LogReferenceChain:     Level /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout:PersistentLevel->OwningWorld
[2015.06.26-20.37.37:268][727]LogReferenceChain:       (target) World /Game/Maps/World0/Level1/Level1_Layout.Level1_Layout
Fatal error: [File:D:\LAG\Bump\Project\master\Engine\Source\Developer\MessageLog\Private\Model\MessageLogListingModel.cpp] [Line: 70] 
Critical Error Package /Game/Maps/World0/Level1/Level1_Layout Object from PIE level still referenced. Shortest path from root:    (Object is not currently rooted)

Hi ,

Thank you for letting us know about this. I was able to reproduce the crash that you described. I located an existing report about this crash, and it appears to have been fixed internally since the crash no longer occurs in our latest internal build. If you are using a binary version of the Engine, this will be corrected in a future release version. If you have built the Engine from source code, the reported fix for this crash can be found here. However, there may be other prerequisite fixes for this fix to work, and I am not sure what those are.