TITLE: Audio stuttering, whistling sounds, and complete audio loss in Unreal Engine 4/5 games on Windows 11 25H2 after KB5077181
SUMMARY:
Since the Windows 11 25H2 updates released in January/February 2026 (specifically KB5077181), I experience progressive audio failure in all Unreal Engine 4 & 5 games. Audio was fully stable in December 2025 on the previous build.
SYSTEM SPECS:
- OS: Windows 11 Pro 25H2 - Build 26200.8117
- CPU: AMD Ryzen 7 3700X (8-Core, 16 Logical Processors @ 4200MHz)
- GPU: NVIDIA RTX 4070 Ti 12GB (MSI Ventus 2X OC)
- RAM: 64GB DDR4 3200MHz Crucial Pro (2x32GB) - A-XMP Profile 1 enabled
- Motherboard: MSI MPG X570 Gaming Plus (MS-7C37)
- PSU: Thermaltake 1000W
- Audio Device: 3.5mm In-Ear Monitors via High Definition Audio (onboard)
- Audio Format: 24-bit, 48000Hz
AFFECTED GAMES (all Unreal Engine 5)
- Grey Zone Warfare
- STALKER 2: Heart of Chernobyl
- Satisfactory
AFFECTED GAMES (Unreal Engine 4):
- Insurgency: Sandstorm
SYMPTOMS (in order of progression):
- Audio begins producing whistling/screeching sounds during gameplay
- Audio stutters rhythmically
- Complete audio loss — all in-game sounds stop entirely
- Audio only recovers when forcing a system change such as switching upscaler (FSR ↔ DLSS) or changing audio input settings in-game
- Issue occurs consistently across all three UE5 titles listed above
TROUBLESHOOTING ALREADY PERFORMED (without resolution):
- Removed all GPU/CPU overclocks
- Disabled all overlays (GeForce Experience, Steam, Discord)
- Cleaned and reconfigured Engine.ini for UE4/UE5 (XAudio2 backend, buffer sizes)
- Optimized Steam launch parameters
- Disabled Nahimic and all third-party audio software (none installed)
- Verified audio drivers are up to date
- Confirmed Windows Audio and Windows Audio Endpoint Builder services are Running/Automatic with Restart on failure
- Set audio two different formats 16/24-bit 44100/48000Hz in Windows Sound settings
- Disabled Fullscreen Optimizations per-game
- Increased audio scheduling priority via registry
- Disconnected secondary USB audio device (SteelSeries Arctis Nova 7P dongle)
- Confirmed only one GameInput Service instance running
- Memory Integrity (VBS Core Isolation) disabled
KEY OBSERVATION:
The problem is EXCLUSIVELY present in Unreal Engine 4 & 5 titles. Different engine games remain perfectly stable on the same system with the same audio configuration. This strongly suggests a conflict between Windows 11 25H2 (post-KB5077181) & the UE4/UE5 audio pipeline (XAudio2/WASAPI).
The audio failure pattern — whistling → stuttering → complete loss → recovery only on forced system change — indicates the audio subsystem loses its device reference during UE4/UE5 runtime and requires an event trigger to re-initialize.
REQUESTED ACTION:
Please investigate the compatibility between Windows 11 25H2 builds post-KB5077181 and the UE4/UE5 XAudio2/WASAPI audio pipeline, particularly on AMD Ryzen systems with onboard High Definition Audio or USB devices.