fresh 5.1 install, EXCEPTION_ACCESS_VIOLATION 0x000 (with pointers)

Development Getting Started & Setup
1

Hi!

I have a fresh install of 5.1, I am only opening the engine itself for a fresh project (not opening an existing project)

I always crashes at 75%. After googling it was suggested on other threads to download pointers for better debugging, so I did and of course it still crashes, here is the crash log with pointers.

I have re-downloaded the whole engine
I have used the “verify” feature to validate all data
The only plugin that is installed is Quixel (default)
I also removed quixel, same crash
It crashes the same when I open any project, always at 75%
I have tried removing ALL components except core and pointers, same crash

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000000

UnrealEditor_UdpMessaging!UE::UdpMessaging::Private::DoJoinMulticastGroup() [D:\build\++UE5\Sync\Engine\Plugins\Messaging\UdpMessaging\Source\UdpMessaging\Private\Transport\UdpMessageTransport.cpp:162]
UnrealEditor_UdpMessaging!UE::UdpMessaging::Private::JoinedToGroup() [D:\build\++UE5\Sync\Engine\Plugins\Messaging\UdpMessaging\Source\UdpMessaging\Private\Transport\UdpMessageTransport.cpp:184]
UnrealEditor_UdpMessaging!FUdpMessageTransport::StartTransport() [D:\build\++UE5\Sync\Engine\Plugins\Messaging\UdpMessaging\Source\UdpMessaging\Private\Transport\UdpMessageTransport.cpp:244]
UnrealEditor_Messaging!FMessageBridge::Enable() [D:\build\++UE5\Sync\Engine\Source\Runtime\Messaging\Private\Bridge\MessageBridge.cpp:81]
UnrealEditor_UdpMessaging!FMessageBridgeBuilder::Build() [D:\build\++UE5\Sync\Engine\Source\Runtime\MessagingCommon\Public\MessageBridgeBuilder.h:109]
UnrealEditor_UdpMessaging!FUdpMessagingModule::InitializeBridge() [D:\build\++UE5\Sync\Engine\Plugins\Messaging\UdpMessaging\Source\UdpMessaging\Private\UdpMessagingModule.cpp:556]
UnrealEditor_UdpMessaging!FUdpMessagingModule::RestartServices() [D:\build\++UE5\Sync\Engine\Plugins\Messaging\UdpMessaging\Source\UdpMessaging\Private\UdpMessagingModule.cpp:354]
UnrealEditor_UdpMessaging!FUdpMessagingModule::StartupModule() [D:\build\++UE5\Sync\Engine\Plugins\Messaging\UdpMessaging\Source\UdpMessaging\Private\UdpMessagingModule.cpp:275]
UnrealEditor_Core!FModuleManager::LoadModuleWithFailureReason() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Modules\ModuleManager.cpp:617]
UnrealEditor_Projects!FModuleDescriptor::LoadModulesForPhase() [D:\build\++UE5\Sync\Engine\Source\Runtime\Projects\Private\ModuleDescriptor.cpp:696]
UnrealEditor_Projects!FPluginManager::TryLoadModulesForPlugin() [D:\build\++UE5\Sync\Engine\Source\Runtime\Projects\Private\PluginManager.cpp:2078]
UnrealEditor_Projects!FPluginManager::LoadModulesForEnabledPlugins() [D:\build\++UE5\Sync\Engine\Source\Runtime\Projects\Private\PluginManager.cpp:2154]
UnrealEditor!FEngineLoop::LoadStartupModules() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:4179]
UnrealEditor!FEngineLoop::PreInitPostStartupScreen() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:3521]
UnrealEditor!GuardedMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:154]
UnrealEditor!GuardedMainWrapper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:107]
UnrealEditor!LaunchWindowsStartup() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:244]
UnrealEditor!WinMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:282]
UnrealEditor!__scrt_common_main_seh() [D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll
2

I had an epiphany, reading the crash log file generated after the crash, the last line always was

FUdpSocketBuilder: Failed to bind UdpMessageMulticastSocket to 0.0.0.0:6666. Error code 3.

Googling that results in many posts showing where this error is generated when the engine is running already, basically in-editor, so I dismissed it as a cause for a complete crash.
However after posting here I decided to go deeper with this error, and used

netstat -ano

to find which process may have port 6666 on UDP open
sample output would be:

UDP    0.0.0.0:6666           *:*                                    12952

Where the last entry - 12952 in my case - is the process ID that has that port open already, and then used task managers Details Tab to find the corresponding process and kill it. For me it was a TeamSpeak server running on that port. Now the engine starts normally.

@anonymous_user_584ef2261 else who might come accross this post in the future, try that
@epic maybe include some descriptive error in the crash log window, if that window had said (before pointers) that it crashed because of UDP port 6666, I would have found this much much much much sooner, the info is already there it seems, just not in the place that is shown to the user on crash

3

6666 is a rather strange choice of port if you ask me, they could have chosen something more random - or better, let the OS assign an available port