Bluetooth Missing from Settings, Restore the Toggle
Bluetooth missing from Settings entirely, with no toggle in Quick Settings and no Bluetooth section in Settings, means Windows has lost contact with the Bluetooth hardware. Wi-Fi usually keeps working, because the two radios share a card but are handled separately, and the fix is to reset the hardware state and make Windows see the adapter again.
Fix it, in order
Do a full cold shutdown. Hold Shift, select Start, then Power, then Shut down, and wait one minute after the PC turns off. On a laptop, also unplug the charger and hold the power button for 30 seconds. A normal restart does not reset the Bluetooth chip, and this step alone restores the toggle in many cases.
Check Airplane mode and the radio key. Press Win + A and make sure Airplane mode is off. Some laptops have a function key that switches the wireless radios off, and Bluetooth stays hidden while that is engaged.
Look for hidden devices in Device Manager. Right-click Start, select Device Manager, select View, then Show hidden devices. If a greyed-out Bluetooth category appears, expand it and read the adapter's status in Properties.
Read the error code on the hidden adapter. A Code 45 means Windows thinks the hardware is not connected, which points to the cold shutdown and the card seating. A Code 43 means the driver reported a failure, which points to a driver reinstall.
Uninstall hidden Bluetooth entries and restart. Right-click each greyed-out Bluetooth entry and select Uninstall device, then restart the PC. Windows re-detects the hardware on boot and reinstalls the driver.
Install the wireless driver from the PC maker. Download the Wi-Fi and Bluetooth driver package for your exact model from the maker's support site. The two radios share one card on most laptops, so the combined package is the correct reinstall.
Check the firmware setting. Restart into the BIOS or UEFI setup and look for a Wireless or Bluetooth setting under Advanced or Configuration. If Bluetooth is disabled there, Windows never sees the adapter at all.
Restart the Bluetooth Support Service. Press Win + R, type services.msc, and press Enter. Find Bluetooth Support Service, set its Startup type to Manual if it is Disabled, and select Start.
If the Bluetooth category never appears in Device Manager, even with hidden devices shown, Windows has no Bluetooth hardware to talk to. Check the firmware setting and the card itself before reinstalling Windows.
If it still happens
If the toggle returns after a cold shutdown but vanishes again after every sleep or restart, the wireless card is likely losing power state. Turn off Fast Startup in Control Panel, Power Options, Choose what the power buttons do, and update the firmware from the PC maker's site. A card that keeps disappearing across cold boots and clean driver installs is usually failing hardware.
Common questions
Wi-Fi works but Bluetooth is gone. How is that possible? Most laptops use one combo card for Wi-Fi and Bluetooth, with Bluetooth running over an internal USB connection. That USB link can lock up while Wi-Fi keeps working, which is why a cold shutdown fixes it and a restart does not.
Bluetooth vanished after the laptop woke from sleep. Why? The Bluetooth half of the wireless card did not wake up with the rest of the system. A full shutdown clears it, and turning off Fast Startup reduces how often it happens.
Is there a Windows setting that hides Bluetooth? No. There is no setting that removes the Bluetooth section from Settings. If it is gone, Windows cannot see the adapter, so the problem is the driver, the service, the firmware setting, or the hardware.