Toggle the Switch: Check your keyboard for a Function key (F-key) with a Bluetooth icon. You may need to press Fn + F_key to enable the radio physically.
Restart the Service: Press Windows Key + R, type services.msc, and press Enter. Find Bluetooth Support Service, right-click it, and ensure it is set to Automatic and is Running.
Airplane Mode: Ensure Airplane mode is turned off in your Windows settings.
Buffering: ring buffers with pre-allocated URBs for low allocation overhead.
Error recovery: on STALL or EPIPE, reset endpoint and re-submit URBs; on repeated failures, re-enumerate device.