After importing project from 4.4 to 4.7, editor crashes on startup with 'Assertion failed: !IsRooted()'

Development Programming & Scripting
1

After converting a project from 4.4 to 4.7, I receive a crash when attempting to start the editor. With the process of elimination, I have isolated the problem to a specific blueprint, which can be found here:

Dropbox - SwingingSword.uasset - Simplify your life The attachment system on Answerhub did not allow me to attach it directly to the Question, unfortunately.

By removing this blueprint, the editor will load, but with missing references, of course.

Here is the full text of the crash:

MachineId:F92CAE0C435FFC8475810F9B91FDD6D9
EpicAccountId:347a6aee258d43aa9437953bf511fcee

Unknown exception - code 00000001 (first/second chance not available)

Assertion failed: !IsRooted() [File:d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\public\uobject\UObjectBaseUtility.h] [Line: 75] 

KERNELBASE + 37901 bytes
UE4Editor_Core!FOutputDeviceWindowsError::Serialize() + 292 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:95]
UE4Editor_Core!FOutputDevice::Logf__VA() + 248 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:144]
UE4Editor_Core!FDebug::AssertFailed() + 1079 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:224]
UE4Editor_BlueprintGraph!UK2Node_EditablePinBase::RemoveUserDefinedPin() + 522 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\blueprintgraph\private\k2node_editablepinbase.cpp:51]
UE4Editor_BlueprintGraph!UK2Node_MathExpression::ClearExpression() + 260 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\blueprintgraph\private\k2node_mathexpression.cpp:2424]
UE4Editor_BlueprintGraph!UK2Node_MathExpression::RebuildExpression() + 117 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\blueprintgraph\private\k2node_mathexpression.cpp:2351]
UE4Editor_BlueprintGraph!UK2Node_MathExpression::ReconstructNode() + 81 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\blueprintgraph\private\k2node_mathexpression.cpp:2506]
UE4Editor_BlueprintGraph!UEdGraphSchema_K2::ReconstructNode() + 553 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\blueprintgraph\private\edgraphschema_k2.cpp:3567]
UE4Editor_UnrealEd!FBlueprintEditorUtils::RefreshAllNodes() + 399 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\kismet2\blueprinteditorutils.cpp:293]
UE4Editor_UnrealEd!FBlueprintEditorUtils::RegenerateBlueprintClass() + 1613 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\kismet2\blueprinteditorutils.cpp:1207]
UE4Editor_CoreUObject!ULinkerLoad::RegenerateBlueprintClass() + 1079 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\blueprint\blueprintsupport.cpp:289]
UE4Editor_CoreUObject!ULinkerLoad::FinalizeBlueprint() + 533 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\blueprint\blueprintsupport.cpp:1000]
UE4Editor_CoreUObject!ULinkerLoad::Preload() + 3645 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3014]
UE4Editor_CoreUObject!ULinkerLoad::CreateExport() + 5845 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3606]
UE4Editor_CoreUObject!ULinkerLoad::IndexToObject() + 152 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3804]
UE4Editor_CoreUObject!ULinkerLoad::CreateExport() + 3505 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3329]
UE4Editor_CoreUObject!ULinkerLoad::IndexToObject() + 152 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3804]
UE4Editor_CoreUObject!ULinkerLoad::CreateExport() + 3505 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3329]
UE4Editor_CoreUObject!ULinkerLoad::CreateExportAndPreload() + 27 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2520]
UE4Editor_CoreUObject!ULinkerLoad::LoadAllObjects() + 603 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2628]
UE4Editor_CoreUObject!LoadPackageInternal() + 2055 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:896]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImportInner() + 1195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2213]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImport() + 195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1978]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImportInner() + 2153 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2261]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImport() + 195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1978]
UE4Editor_CoreUObject!ULinkerLoad::Verify() + 807 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1768]
UE4Editor_CoreUObject!ULinkerLoad::FinalizeCreation() + 432 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1674]
UE4Editor_CoreUObject!ULinkerLoad::Tick() + 336 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:634]
UE4Editor_CoreUObject!ULinkerLoad::CreateLinker() + 111 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:382]
UE4Editor_CoreUObject!GetPackageLinker() + 2546 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linker.cpp:668]
UE4Editor_CoreUObject!LoadPackageInternal() + 1567 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:833]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImportInner() + 1195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2213]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImport() + 195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1978]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImportInner() + 2153 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2261]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImport() + 195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1978]
UE4Editor_CoreUObject!ULinkerLoad::Verify() + 807 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1768]
UE4Editor_CoreUObject!ULinkerLoad::FinalizeCreation() + 432 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1674]
UE4Editor_CoreUObject!ULinkerLoad::Tick() + 336 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:634]
UE4Editor_CoreUObject!ULinkerLoad::CreateLinker() + 111 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:382]
UE4Editor_CoreUObject!GetPackageLinker() + 2546 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linker.cpp:668]
UE4Editor_CoreUObject!LoadPackageInternal() + 1567 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:833]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImportInner() + 1195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2213]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImport() + 195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1978]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImportInner() + 2153 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2261]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImport() + 195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1978]
UE4Editor_CoreUObject!ULinkerLoad::Verify() + 807 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1768]
UE4Editor_CoreUObject!ULinkerLoad::FinalizeCreation() + 432 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1674]
UE4Editor_CoreUObject!ULinkerLoad::Tick() + 336 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:634]
UE4Editor_CoreUObject!ULinkerLoad::CreateLinker() + 111 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:382]
UE4Editor_CoreUObject!GetPackageLinker() + 2546 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linker.cpp:668]
UE4Editor_CoreUObject!LoadPackageInternal() + 1567 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:833]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImportInner() + 1195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2213]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImport() + 195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1978]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImportInner() + 2153 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2261]
UE4Editor_CoreUObject!ULinkerLoad::VerifyImport() + 195 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1978]
UE4Editor_CoreUObject!ULinkerLoad::Verify() + 807 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1768]
UE4Editor_CoreUObject!ULinkerLoad::FinalizeCreation() + 432 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1674]
UE4Editor_CoreUObject!ULinkerLoad::Tick() + 336 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:634]
UE4Editor_CoreUObject!ULinkerLoad::CreateLinker() + 111 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:382]
UE4Editor_CoreUObject!GetPackageLinker() + 2546 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\linker.cpp:668]
UE4Editor_CoreUObject!LoadPackageInternal() + 1567 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:833]
UE4Editor_CoreUObject!ResolveName() + 1483 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:610]
UE4Editor_CoreUObject!StaticLoadObject() + 655 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:697]
UE4Editor_CoreUObject!StaticLoadClass() + 167 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:760]
UE4Editor_Amorphous!ConstructorHelpersInternal::FindOrLoadClass() + 1020 bytes [g:\ue4\unreal engine\4.7\engine\source\runtime\coreuobject\public\uobject\constructorhelpers.h:75]
UE4Editor_Amorphous!ConstructorHelpers::FClassFinder<APawn>::FClassFinder<APawn>() + 201 bytes [g:\ue4\unreal engine\4.7\engine\source\runtime\coreuobject\public\uobject\constructorhelpers.h:142]
UE4Editor_Amorphous!AAmorphousGameMode::AAmorphousGameMode() + 214 bytes [g:\ue4\projects\amorphous 4.7\source\amorphous\private\amorphousgamemode.cpp:22]
UE4Editor_CoreUObject!UClass::CreateDefaultObject() + 435 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\class.cpp:2506]
UE4Editor_CoreUObject!UObjectLoadAllCompiledInDefaultProperties() + 805 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectbase.cpp:739]
UE4Editor_CoreUObject!ProcessNewlyLoadedUObjects() + 146 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\uobjectbase.cpp:815]
UE4Editor_CoreUObject!TBaseStaticDelegateInstance<void __cdecl(void)>::ExecuteIfSafe() + 7 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:921]
UE4Editor_Core!TBaseMulticastDelegate<void>::Broadcast() + 149 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:1030]
UE4Editor_Core!FModuleManager::LoadModuleWithFailureReason() + 2194 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\modules\modulemanager.cpp:359]
UE4Editor_Projects!FModuleDescriptor::LoadModulesForPhase() + 784 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\projects\private\moduledescriptor.cpp:350]
UE4Editor_Projects!FProjectManager::LoadModulesForProject() + 581 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\projects\private\projectmanager.cpp:53]
UE4Editor!FEngineLoop::LoadStartupModules() + 705 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launchengineloop.cpp:1863]
UE4Editor!FEngineLoop::PreInit() + 11141 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launchengineloop.cpp:1400]
UE4Editor!GuardedMain() + 251 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launch.cpp:110]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]
2

Hey JSFitzsimmons,

I can’t reproduce the crash with just that blueprint - it gives me a lot of errors but no crash in 4.7.2. Is there any way you could upload a minimal version of the project that still exhibits the crash? That would be a huge help in fixing this bug.

3

Hey JSFitzsimmons -

I believe we may have found the cause for this issue, but I cannot accurately and dependable reproduce it internally, if at all possible if you could upload a copy of your project, and if you would like to keep it private feel free to link me via the Forums. The issue seems to be Math Expression and casting related.

Let me know -

Eric Ketchum

4

Hi, sorry for the delay, and thanks very much for looking into this.

I have uploaded the source material for the entire project, which happens to be a very tiny experimental project. Here it is: Dropbox - amorphous.7z - Simplify your life (7.6 MB)

5

Hey -

Thank you and sorry for the delay getting back in touch with you. I have entered the bug and included your project which is really helpful for us to test the issue with, thank you again, for reference UE-11851.

I will keep you informed as we work toward a solution

Eric Ketchum