# Assertion failed: MacAddress.Num() == 6 **URL:** \ **Category:** Platform & Builds\ **Tags:** unreal-engine, UE5-0, question, troubleshooting\ **Created:** [April 1, 2022, 1:14am UTC](https://forums.unrealengine.com/t/assertion-failed-macaddress-num-6/511376 "2022-04-01T01:14:22Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![asorgejr](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@asorgejr](https://forums.unrealengine.com/u/asorgejr)\ **Post date:** [April 1, 2022, 1:14am UTC](https://forums.unrealengine.com/t/assertion-failed-macaddress-num-6/511376/1 "2022-04-01T01:14:22Z")
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: ```auto 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 ---
**Author:** ![uJelleh](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@uJelleh](https://forums.unrealengine.com/u/uJelleh)\ **Post date:** [April 9, 2022, 1:29am UTC](https://forums.unrealengine.com/t/assertion-failed-macaddress-num-6/511376/2 "2022-04-09T01:29:06Z")
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. ---
**Author:** ![asorgejr](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@asorgejr](https://forums.unrealengine.com/u/asorgejr)\ **Post date:** [April 9, 2022, 6:16am UTC](https://forums.unrealengine.com/t/assertion-failed-macaddress-num-6/511376/3 "2022-04-09T06:16:31Z")
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! ---
**Author:** ![Spyhabs](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Spyhabs](https://forums.unrealengine.com/u/Spyhabs)\ **Post date:** [January 1, 2023, 10:04pm UTC](https://forums.unrealengine.com/t/assertion-failed-macaddress-num-6/511376/5 "2023-01-01T22:04:01Z")
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 ---
**Author:** ![Xodroc](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Xodroc](https://forums.unrealengine.com/u/Xodroc)\ **Post date:** [June 21, 2023, 6:17pm UTC](https://forums.unrealengine.com/t/assertion-failed-macaddress-num-6/511376/6 "2023-06-21T18:17:50Z")
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. ---
**Author:** ![irfaneali](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@irfaneali](https://forums.unrealengine.com/u/irfaneali)\ **Post date:** [November 26, 2023, 12:03am UTC](https://forums.unrealengine.com/t/assertion-failed-macaddress-num-6/511376/7 "2023-11-26T00:03:09Z")
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.