My headphone connected to my laptop but no audio

# Windows Feedback Report


## Title
Bluetooth headset connects but Windows often fails to create/keep the playback audio endpoint; Windows Security real-time protection also turns off unexpectedly


## Device and Windows version
- Device: LENOVO 21MR, x64-based PC
- Windows edition: Microsoft Windows 11 Home China
- Windows version/build: 10.0.26200, Build 26200
- Last observed boot time: 2026-06-02 21:57:18, Asia/Shanghai


## Primary issue: Bluetooth headset connected but no sound
Device: soundcore Space One Bluetooth headset


### Expected behavior
After the headset connects over Bluetooth, Windows should automatically expose a playback output endpoint named "Headphones / Earphone (soundcore Space One)", keep it present after reboot, and route audio to it when selected as the default output device.


### Actual behavior
The headset appears connected at the Bluetooth and A2DP driver level, but Windows often does not create or keep the playback AudioEndpoint. The headset controls can still pause/play media, but no audio is heard.


Observed states:
- Bluetooth device is OK:
  - `soundcore Space One`
  - `BTHENUM\DEV_F49D8A281CD7\...\BLUETOOTHDEVICE_F49D8A281CD7`
- A2DP media device is OK:
  - `soundcore Space One`
  - `BTHENUM\{0000110B-0000-1000-8000-00805F9B34FB}_LOCALMFG&0002\...\F49D8A281CD7_C00000000`
  - Driver: `microsoft_bluetooth_a2dp_src.inf`
- AVRCP transport devices are OK:
  - `soundcore Space One Avrcp Transport`
- Intel Bluetooth audio components are present:
  - `适用于蓝牙® 音频的英特尔® 智音技术`
  - `Intel® Smart Sound Technology for Bluetooth® LE Audio`
- The AudioEndpoint for `耳机 (soundcore Space One)` is intermittent:
  - Sometimes it is missing from `Get-PnpDevice -Class AudioEndpoint -PresentOnly`
  - Sometimes it exists but sound still does not play
  - Previously observed stale endpoints with `IsPresent=False`
- `pnputil /restart-device` sometimes reports that the device is waiting for a system restart to complete a previous operation.


### Troubleshooting already attempted
- Re-paired the Bluetooth headset.
- Restarted Windows Audio, Windows Audio Endpoint Builder, Bluetooth Support Service, and Bluetooth user service.
- Reinstalled or repaired Bluetooth driver stack previously.
- Restarted soundcore Bluetooth / MEDIA / AVRCP / Hands-Free PnP nodes with `pnputil /restart-device`.
- Scanned hardware changes with `pnputil /scan-devices`.
- Set `耳机 (soundcore Space One)` as default output when the endpoint appears.
- Unmuted and set endpoint volume to 75%.
- Rebooted the PC.


### Impact
Bluetooth appears connected, but audio output is unusable or unstable. The problem returns after reboot or after driver/device refresh. This looks like a Windows Bluetooth audio endpoint / A2DP / AudioEndpointBuilder issue rather than a simple default-output selection issue.


## Secondary issue: Windows Security protection turns off unexpectedly
Windows Security / Microsoft Defender status was observed as:
- `AMServiceEnabled: False`
- `AntivirusEnabled: False`
- `RealTimeProtectionEnabled: False`
- `AntispywareEnabled: False`
- `AMEngineVersion: 0.0.0.0`


Earlier, Defender detected and handled:
- `C:\Users\20812\AppData\Local\Temp\3dm_smzd.exe`
- Threat ID mapped to `Trojan:Win32/Vigorf.A`
- Action success was reported as True


Expected behavior: Windows Security real-time protection should remain enabled and clearly explain why it is disabled if another security product or policy is controlling it.


## Additional background-app issue
Several apps repeatedly start or run in the background after being closed, including:
- UU cloud gaming
- WPS
- Meitu Xiuxiu
- Intel Graphics Software


Expected behavior: Windows should provide clearer and more reliable controls to prevent unwanted background startup or relaunch behavior.


## Requested Microsoft investigation
Please investigate:
1. Why Windows 11 Build 26200 fails to reliably create/keep the Bluetooth A2DP playback AudioEndpoint for soundcore Space One even when the Bluetooth and A2DP PnP nodes are OK.
2. Whether Intel Smart Sound Technology for Bluetooth Audio / Bluetooth LE Audio is interacting badly with classic A2DP endpoints.
3. Why `pnputil /restart-device` may leave the Bluetooth audio device waiting for reboot or fail to restore the audio endpoint.
4. Why Windows Security / Defender status shows protection disabled with engine version `0.0.0.0`.
5. How Windows can better surface and control persistent third-party background startup behavior.