Reset Allow USB Debugging? Notification

1. Go to C:\Users\<YourProfile>\.android and delete both adbkey files, if there are none, skip this step.
2. Download adb here and extract it somewhere.
3. Open command prompt and navigate to the folder you’ve just extracted, for example 
   cd C:\path\to\platform-tools
   ※right click on the unzipped folder and select Open in Terminal also work.
4. With the headset connected and logged in an administrator account, run .\adb kill-server and then .\adb devices.
5. The notification should appear.

The “Toggle” Fix (Most Common Solution)

The Developer Mode status can sometimes desync between the headset and the mobile app.

1. Open the Meta Horizon (Quest) App on your phone.
2. Navigate to Menu > Devices > Headset Settings > Developer Mode.
3. Toggle the switch OFF, wait about 10 seconds, and then toggle it back ON.
4. Restart your headset (hold the power button and select Restart).
5. Plug it back into your PC; the prompt should now appear.