Hello,
I tried to migrate a copy of my project overview 4.12.5 to 4.13 and there is a bug in the launch on my map by default (persistent level).
To reproduce the bug I create an empty project with a persistent map and two sub levels that contain landscape (the error of the crash speaks of a mistake on the landscape.cpp)
Assertion failed: LandscapeActor || LandscapeActor == Landscape [File:D:\Build\++UE4+Release-4.13+Compile\Sync\Engine\Source\Runtime\Landscape\Private\Landscape.cpp] [Line: 1784]
UE4Editor_Core! :: FDebug AssertFailed () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\core\private\misc\outputdevice.cpp:421]
UE4Editor_Landscape! :: ULandscapeInfo RegisterActor () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\landscape\private\landscape.cpp:1785]
UE4Editor_Landscape ALandscapeProxy :: CreateLandscapeInfo ()! [D: \ build \ ++ EU4 + 4.13 + release-compiled \ sync \ engine \ source \ runtime \ landscape \ private \ landscape.cpp: 718]
UE4Editor_Landscape! ALandscapeProxy :: PostLoad () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\landscape\private\landscape.cpp:1430]
UE4Editor_CoreUObject! UObject :: ConditionalPostLoad () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\private\uobject\obj.cpp:810]
UE4Editor_CoreUObject! :: FAsyncPackage PostLoadObjects () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:2212]
UE4Editor_CoreUObject! FAsyncPackage :: Tick () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:1414]
UE4Editor_CoreUObject! :: FAsyncLoadingThread ProcessAsyncLoading () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:722]
UE4Editor_CoreUObject! :: FAsyncLoadingThread TickAsyncThread () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:1001]
UE4Editor_CoreUObject! :: FAsyncLoadingThread TickAsyncLoading () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:898]
UE4Editor_CoreUObject! FlushAsyncLoading () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:2649]
UE4Editor_Engine! :: ULevelStreaming RequestLevel () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\engine\private\levelstreaming.cpp:499]
UE4Editor_Engine UWorld :: UpdateLevelStreamingInner ()! [D: \ build \ ++ EU4 + 4.13 + release-compiled \ sync \ engine \ source \ runtime \ engine \ private \ world.cpp: 2508]
! UE4Editor_Engine UWorld :: UpdateLevelStreaming () [d: \ build \ ++ EU4 + 4.13 + release-compiled \ sync \ engine \ source \ runtime \ engine \ private \ world.cpp: 2582]
! UE4Editor_Engine UWorld :: FlushLevelStreaming () [d: \ build \ ++ EU4 + 4.13 + release-compiled \ sync \ engine \ source \ runtime \ engine \ private \ world.cpp 2611]
UE4Editor_UnrealEd! :: UEditorEngine Map_Load () [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\editorserver.cpp:2493]
UE4Editor_UnrealEd! :: UEditorEngine HandleMapCommand () [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\editorserver.cpp:5998]
UE4Editor_UnrealEd! UEditorEngine :: Exec () [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\editorserver.cpp:5479]
UE4Editor_UnrealEd UUnrealEdEngine :: Exec ()! [D: \ build \ ++ EU4 + 4.13 + release-compiled \ sync \ engine \ source \ editor \ UnrealEd \ private \ unrealedsrv.cpp: 624]
UE4Editor_UnrealEd! FEditorFileUtils :: LoadMap () [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\filehelpers.cpp:2178]
UE4Editor_UnrealEd! :: FEditorFileUtils LoadDefaultMapAtStartup () [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\filehelpers.cpp:3408]
UE4Editor_UnrealEd! FUnrealEdMisc :: OnInit () [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\unrealedmisc.cpp:302]
UE4Editor_UnrealEd EditorInit ()! [D: \ build \ ++ EU4 + 4.13 + release-compiled \ sync \ engine \ source \ editor \ UnrealEd \ private \ unrealed.cpp: 89]
UE4Editor GuardedMain ()! [D: \ build \ ++ EU4 + 4.13 + release-compiled \ sync \ engine \ source \ runtime \ launch \ private \ launch.cpp: 140]
UE4Editor! GuardedMainWrapper () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor! WinMain () [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor scrt_common_main_seh __ () [f: \ dd \ vctools \ crt \ vcstartup \ src \ startup \ exe_common.inl: 264]!
kernel32
ntdll
So my map persistent handles well and contains my two levels with the landscape but if I duplicate a level with a landscape in and I added in my levels under persistent level this crash and I get the error message above.
I joined a project that reproduces the bug. simply duplicate an existing level, which is in a persistent map and add it.
I hope it will be corrected in a future preview or at least in version 4.13 Final otherwise I could not migrate my project.
Thank you.