Lenovo Yoga 9i 2-in-1 Gen 9 Bluetooth is missing, will not pair or disconnects

The checks in more detail

If the list of devices is empty or the Bluetooth switch is missing, open Device Manager and look for the Bluetooth entry; a yellow mark means the driver has a problem. Update the Bluetooth and the Wi-Fi drivers through Lenovo Vantage, since in many Lenovo laptops the same wireless card handles both. Run the Windows Bluetooth troubleshooter. Restart the laptop, which clears many glitches. Fast Startup can leave the radio in a bad state, and a full shut down rather than a restart sometimes helps. Interference matters. Bluetooth shares the 2.4 gigahertz band with Wi-Fi and microwaves;

keep the accessory near the laptop, and move away from USB 3 hubs and drives, which are known to give off noise in that band. If audio stutters, try changing the Wi-Fi to the 5 gigahertz band. Keep the accessory's own firmware up to date, as many headphones update through an app. On a 2-in-1, tent and tablet modes can change how the antenna sits relative to your hands, so test in laptop mode. If nothing works, a BIOS update may include a fix. Contact Lenovo with the serial number if Bluetooth disappears from Device Manager altogether, which suggests a hardware fault.

The Yoga 9i 2-in-1 has a rotating soundbar hinge on some models and a metal body, so the antennas sit in the edges, and a case or a hand over the hinge can affect Bluetooth range. Try the accessory within a meter of the left or right edge of the laptop. If you use the laptop in tent or stand mode, test again in laptop mode. Lenovo Vantage has a Hardware Settings section and an Update section; install the Bluetooth firmware updates if offered. A stuck Bluetooth service can be restarted in Services by restarting Bluetooth Support Service.