Lenovo Legion Pro 7i Gen 9 Bluetooth is missing, will not pair or disconnects

The checks in more detail

Restart the laptop. If Bluetooth is missing or the toggle is grayed out, open Device Manager and look for the Bluetooth entry; a mark or a missing entry means a driver problem, which you fix by uninstalling the Bluetooth device and restarting so that Windows reinstalls it, or by installing the latest wireless and Bluetooth driver from Lenovo's page or Intel.

Check the Bluetooth Support Service in the Services list: it must be running and set to start automatically. In the properties of the Bluetooth adapter in Device Manager, on the Power Management tab, untick the option that lets Windows turn it off to save power, since drops after idle often come from that. Interference is common on gaming desks: a USB 3 hub, a wireless mouse dongle and a 2.4 GHz router near the laptop can disrupt a headset, so move the hub, use a USB extension and try the 5 GHz band for Wi-Fi. For a headset, set it as the default device and choose the right profile, since the hands-free profile has lower quality than the stereo profile, and some headsets switch when the microphone is used.

Update the headset's firmware. On a game controller, use its wired mode to confirm it works. Update the BIOS. Test with a second device to see whether the laptop or the accessory is at fault. If Bluetooth vanishes after all steps, the card may need replacing under warranty. On this laptop the usual trouble is the gaming kit around it. Many headsets and mice use their own USB receiver and ignore Bluetooth entirely, so confirm which link the device uses before debugging: a headset connected through a receiver will not appear in the Bluetooth list at all. Controllers such as Xbox pads pair over Bluetooth, but they pair to one device at a time,

so a pad that was last used on a console has to be put back in pairing mode with the pairing button held until the light flickers. If the Bluetooth radio shares the 2.4 GHz band with a wireless mouse receiver, move the receiver to a rear port or onto an extension cable, and keep the laptop's vents clear so heat does not disturb the card. Audio over Bluetooth adds latency, which suits music and not fast games, so for competitive play use a wired headset or the receiver that came with it. After a Windows feature update the Bluetooth driver can be replaced by an older generic one, so check that the version in Device Manager matches the one from Lenovo, and reinstall it if not.