Unpairing Bluetooth smartphone

If you have already paired a phone with Windows to provide FIDO passkeys over Bluetooth, it will appear in the credentials dialog box.

When an exisiting phone is an option, AuthenticatorChooser will pre-select the Security key option, but will not submit it, in case you want to use the phone option.

To remove the phone option, you can delete the subkey in HKEY_USERS\S-1-5-20\Software\Microsoft\Cryptography\FIDO\<Your user SID>\LinkedDevices which has its Name value set to the phone's name that you want to remove.

You may also back up or rename the subkey if you want to restore it later. Changes take effect the next time the credential prompt appears, without needing to sign out or reboot first.