Arc Raiders Hang Detected on GameThread Crash

What is the Arc Raiders "Hang detected on GameThread" crash?

After Embark Studios pushed the late-May 2026 server-side patch to Arc Raiders, players started seeing the game freeze for ~30 seconds then exit with the Unreal Engine 5 fatal error window: "LowLevelFatalError [File:Unknown] [Line: 1568] Hang detected on GameThread". Unlike the render-thread crashes covered in our exception-access-violation article, this one fires on UE5's main game thread — meaning the CPU side is stalling, not the GPU. The crash log under %LOCALAPPDATA%\ArcRaiders\Saved\Logs\ArcRaiders.log typically shows the last successful tick logging an LogStreaming or LogPhysics warning right before the hang trigger.

When does it occur?

• During or just after loading into a Topside session, especially Buried City
• When the streaming system loads a new Tile-Layer chunk (e.g., crossing the Stella station threshold)
• After alt-tabbing back into the game following ~5 minutes minimized
• On high-core-count CPUs (Ryzen 9 7950X3D, Intel i9-14900K) where worker thread affinity is unbalanced
• After applying the patch on top of an older shader cache from build 1.7.x

Common causes

• UE5 task graph thread starvation when the patch enabled a new audio decode async pass
• r.GTSyncType default flipped to 1 (sync to RHI thread) causing back-pressure on GameThread
• Windows 11 24H2 Core Isolation (HVCI) adding latency to UE5 worker context switches
• Discord/NVIDIA overlay hooks (OverlayInjector.dll) blocking the main thread on present
• Corrupted DDC (Derived Data Cache) from upgrading mid-build
• AMD Adrenalin "Smooth Motion" frame generation conflicting with UE5's frame pacer
• Background storage scans (Windows Defender, OneDrive) starving the streaming I/O thread

Step-by-step fixes

1. Add Engine.ini console flags to force GameThread async mode — Open %LOCALAPPDATA%\ArcRaiders\Saved\Config\WindowsClient\Engine.ini and add at the bottom:

   [SystemSettings]
   r.GTSyncType=0
   r.OneFrameThreadLag=1
   r.FinishCurrentFrame=0

This forces the GameThread to stop waiting on the RHI thread and is the single most effective fix players are reporting on the official Embark Discord.

1. Delete the Derived Data Cache — Close the game, delete the entire folder %LOCALAPPDATA%\ArcRaiders\Saved\DerivedDataCache and %LOCALAPPDATA%\UnrealEngine\Common\DerivedDataCache\Local\ArcRaiders. Relaunch — first match will rebuild caches.
2. Disable Discord and NVIDIA in-game overlays — Discord -> Settings -> Game Overlay -> Off for Arc Raiders. NVIDIA App -> Settings -> Overlay -> Off. The OverlayInjector.dll is a known GameThread blocker on UE5 5.4+.
3. Pin Arc Raiders to specific cores on high-core CPUs — Open Task Manager while the game is running, right-click ArcRaiders-Win64-Shipping.exe -> Set Affinity, and on 7950X3D / 14900K limit to the 8 V-Cache or P-Cores only. UE5's automatic affinity assigns work to E-cores, which causes the hang on heterogeneous CPUs.
4. Turn off Core Isolation / Memory Integrity — Windows Security -> Device Security -> Core Isolation Details -> Memory Integrity Off. Reboot. HVCI is documented by Epic to add 5-15% latency to UE5 worker threads.
5. Disable AMD Smooth Motion / NVIDIA Frame Generation — In Adrenalin -> Gaming -> Arc Raiders -> Smooth Motion Off. NVIDIA users: in-game DLSS Frame Generation Off until Embark ships the next pacer fix.
6. Exclude the Arc Raiders folder from Defender / OneDrive — Add C:\Program Files (x86)\Steam\steamapps\common\Arc Raiders (or the Epic path) as an exclusion in Windows Security -> Virus & threat protection -> Manage settings -> Add exclusion. Pause OneDrive sync during play.
7. Verify Steam/Epic files and reset network adapter for combo crashes — Steam -> Library -> Arc Raiders -> Properties -> Installed Files -> Verify integrity. Then Win+X -> Terminal (Admin) -> netsh winsock reset && netsh int ip reset -> reboot. This handles the cases where the GameThread hang is actually waiting on a stuck network call.

If it still doesn't work

Pull the last 200 lines of ArcRaiders.log from %LOCALAPPDATA%\ArcRaiders\Saved\Logs\ and post them on the Embark Bug Reports tab of the official Discord with the tag [GAMETHREAD-HANG]. Embark's QA lead Krattan is publicly tracking the post-patch hang and asked for logs showing the last LogStreaming or LogPhysics entry before the freeze. As a temporary workaround until the next hotfix (expected with the mid-June balance patch), launching the game with the Steam command-line argument -norhithread -dx12 -nothreadedrendering runs the engine in single-threaded RHI mode at a frame rate cost but eliminates the hang for nearly all reporters.