My level is crashing

Hi all, I was working on my level and it was all good until I closed it and tried opening again. Now it won’t open.
I’ve tried backup files and they won’t open either.
The crash report says this (see bellow) which leads me to believe it had something to do with foliage
can anyone help?link text

Fatal error: [File:D:\Build++UE4+Release-4.12+Compile\Sync\Engine\Source\Runtime\Foliage\Private\FoliageInstanceBase.cpp] [Line: 90]
Instance base cache - integrity verification(3): Counter: 37 Size: 21, InvSize: 20 (L:1 S:0 T:0)

UE4Editor_Core!FDebug::AssertFailed() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\misc\outputdevice.cpp:440]
UE4Editor_Foliage!operator<<() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\foliage\private\foliageinstancebase.cpp:93]
UE4Editor_Foliage!AInstancedFoliageActor::Serialize() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\foliage\private\instancedfoliage.cpp:2247]
UE4Editor_CoreUObject!FLinkerLoad::Preload() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3293]
UE4Editor_CoreUObject!EndLoad() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1411]
UE4Editor_CoreUObject!LoadPackageInternal() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1171]
UE4Editor_CoreUObject!LoadPackageInternal() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1286]
UE4Editor_CoreUObject!ResolveName() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:696]
UE4Editor_CoreUObject!StaticLoadObjectInternal() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:783]
UE4Editor_CoreUObject!StaticLoadObject() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:853]
UE4Editor_ContentBrowser!FAssetData::GetAsset() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\assetregistry\public\assetdata.h:218]
UE4Editor_ContentBrowser!SContentBrowser::OnAssetsActivated() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\contentbrowser\private\scontentbrowser.cpp:1793]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,SContentBrowser,0,TTypeWrapper __cdecl(TArray const & __ptr64,enum EAssetTypeActivationMethod::Type)>::Execute() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:321]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,SContentBrowser,0,void __cdecl(TArray const & __ptr64,enum EAssetTypeActivationMethod::Type)>::ExecuteIfSafe() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:428]
UE4Editor_ContentBrowser!TBaseDelegate const & __ptr64,enum EAssetTypeActivationMethod::Type>::ExecuteIfBound() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:608]
UE4Editor_ContentBrowser!SAssetView::OnListMouseButtonDoubleClick() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\contentbrowser\private\sassetview.cpp:3545]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,SAssetView,0,TTypeWrapper __cdecl(TSharedPtr)>::Execute() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:321]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,SAssetView,0,void __cdecl(TSharedPtr)>::ExecuteIfSafe() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:428]
UE4Editor_ContentBrowser!TBaseDelegate >::ExecuteIfBound() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:608]
UE4Editor_ContentBrowser!SListView >::Private_OnItemDoubleClicked() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\public\widgets\views\slistview.h:698]
UE4Editor_ContentBrowser!STableRow >::OnMouseButtonDoubleClick() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\public\widgets\views\stablerow.h:264]
UE4Editor_Slate!::operator()() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4986]
UE4Editor_Slate!FEventRouter::Route >() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:215]
UE4Editor_Slate!FSlateApplication::RoutePointerDoubleClickEvent() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4984]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonDoubleClickEvent() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4969]
UE4Editor_Slate!FSlateApplication::OnMouseDoubleClick() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4947]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:1514]
UE4Editor_Core!FWindowsApplication::DeferMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:1850]
UE4Editor_Core!FWindowsApplication::ProcessMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:745]
UE4Editor_Core!FWindowsApplication::AppWndProc() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:667]
user32
user32
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:903]
UE4Editor!FEngineLoop::Tick() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:2729]
UE4Editor!GuardedMain() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launch.cpp:148]
UE4Editor!GuardedMainWrapper() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll

Hi,

Unfortunately only workaround in 4.12 is to change editor code and make a custom build.

In 4.13 this bug was fixed and if you open your project in 4.13 preview 1 build it should not crash anymore.