The most common cause is simply that the adapter isn't active.
Some motherboards and laptops have a hardware-level toggle for Bluetooth and Wi-Fi inside the BIOS. If disabled there, Windows cannot see the radio at all. bthps3 bluetooth host radio not found
The driver may be looking for the radio before Windows has fully powered it on. The most common cause is simply that the
Additionally, in Control Panel > Power Options > Change plan settings > Change advanced power settings: Some motherboards and laptops have a hardware-level toggle