Assertion failed: MacAddress.Num() == 6

Development Platform & Builds
, , ,
1

I’m running UE 5.0.0 (Preview 2) on Windows 10. The editor crashes when trying to open my World Partition level.
The issue happens after I close Unreal and try to reopen. It will continue to crash with the same error until I restart my computer. After restarting, it will work properly until I have to close and reopen again.

Any suggestions on how to fix this?

Here’s the traceback from the crash window:

LoginId: ***

EpicAccountId: ***

Assertion failed: MacAddress.Num() == 6 [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\LevelActor.cpp] [Line: 292]

UnrealEditor_Engine!FActorSpawnUtils::MakeUniqueActorName() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\LevelActor.cpp:340]

UnrealEditor_Engine!UWorld::SpawnActor() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\LevelActor.cpp:564]

UnrealEditor_Engine!UWorld::SpawnActor() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\LevelActor.cpp:438]

UnrealEditor_Engine!UChildActorComponent::CreateChildActor() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\Components\ChildActorComponent.cpp:671]

UnrealEditor_Engine!UActorComponent::ExecuteRegisterEvents() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\Components\ActorComponent.cpp:1628]

UnrealEditor_Engine!UActorComponent::RegisterComponentWithWorld() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\Components\ActorComponent.cpp:1283]

UnrealEditor_Engine!USimpleConstructionScript::RegisterInstancedComponent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\SimpleConstructionScript.cpp:634]

UnrealEditor_Engine!USCS_Node::ExecuteNodeOnActor() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\SCS_Node.cpp:163]

UnrealEditor_Engine!USCS_Node::ExecuteNodeOnActor() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\SCS_Node.cpp:202]

UnrealEditor_Engine!USimpleConstructionScript::ExecuteScriptOnActor() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\SimpleConstructionScript.cpp:643]

UnrealEditor_Engine!AActor::ExecuteConstruction() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\ActorConstruction.cpp:780]

UnrealEditor_Engine!AActor::RerunConstructionScripts() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\ActorConstruction.cpp:535]

UnrealEditor_Engine!ULevel::IncrementalRunConstructionScripts() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\Level.cpp:1518]

UnrealEditor_Engine!ULevel::IncrementalUpdateComponents() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\Level.cpp:1396]

UnrealEditor_Engine!UWorld::UpdateWorldComponents() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\World.cpp:2268]

UnrealEditor_UnrealEd!UEditorEngine::Map_Load() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\EditorServer.cpp:2802]

UnrealEditor_UnrealEd!UEditorEngine::HandleMapCommand() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\EditorServer.cpp:6232]

UnrealEditor_UnrealEd!UEditorEngine::Exec() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\EditorServer.cpp:5722]

UnrealEditor_UnrealEd!UUnrealEdEngine::Exec() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\UnrealEdSrv.cpp:659]

UnrealEditor_UnrealEd!FEditorFileUtils::LoadMap() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\FileHelpers.cpp:2761]

UnrealEditor_UnrealEd!FEditorFileUtils::LoadDefaultMapAtStartup() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\FileHelpers.cpp:4336]

UnrealEditor_UnrealEd!FUnrealEdMisc::OnInit() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\UnrealEdMisc.cpp:359]

UnrealEditor_UnrealEd!EditorInit() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\UnrealEdGlobals.cpp:134]

UnrealEditor!GuardedMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:159]

UnrealEditor!GuardedMainWrapper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:147]

UnrealEditor!LaunchWindowsStartup() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:283]

UnrealEditor!WinMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:330]

UnrealEditor!__scrt_common_main_seh() [d:\a01\_work\6\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]

kernel32

ntdll

Thanks

2

You are not gonna BELIEVE the fix for this (hopefully this fixes for you too). To Epic - wtf lol…

So as it turns out, MacAddress is literally referring to your networks on your PC. 1. I had a ton of disconnected virtual network adapters piled up, so I disabled them all, and now I can place actors in my levels without it crashing.

4 Likes
3

Wow, talk about a ridiculous workaround! As a matter of fact I have a ton of virtual adapters as well so that’s probably it.
Seems this issue is still happening in the latest release. I filed a bug report so hopefully they patch this one up. In the meantime I guess disabling the adapters is the way to go. Thanks for the help!

4

It doesn’t working, do we have any solution else?

5

It’s unbelievable but your solution is working well. I disconnected a ton of virtual network adapters and I can now place a new object on the scene.

Thanks

6

Amazingly I think this is happening to me in 5.2.1 when trying to open the Electric Dreams Main Level. Hopefully I can find some network adapters to disable!

EDIT: Disabling Microsoft Virtual Network adapters that weren’t even being used indeed solved the Electric Dreams crash as well as a crash I was getting with some of my levels when placing actors with Pawn sensing.

7

where to find help for assertion failed mac address unreal engine error. how to solve the issue. the network remedy not work for me. i have only one lan connetion not anything else.