Mac – Bluetooth disappeared. Unknown USB device appeared

bluetoothdriversmacbook pro

Recently my Windows 7 64-bit has found an unknown device in the category of USB controllers. It was not able to find any driver neither on my computer, nor on Windows Update servers. At the same time Bluetooth support and device disappeared.

Simple logic suggests that somehow Windows has lost information about Bluetooth driver and now recognizes it as unknown USB device. Moreover, afaik my internal Bluetooth is connected through USB interface to the main board.

Any suggestions? What should I do to diagnose the problem? How do I fix my Bluetooth w/o reinstalling Windows?

Hardware: MacBook Pro 15" (6.2, mid 2010).

Best Answer

Your MacBook has a Broadcom BCM92070 bluetooth card which is actually an USB dongle. (it's sometimes soldered on some "hybrid" Wi-Fi+Bluetooth mini PCI-e cards but they work separately; see the linked question at the end if you're curious)

That "dongle" requires a firmware to be loaded before it can be used, and it appears that some communication with it (what exactly ? I don't know) may brick it until the next poweroff (a reboot won't do). Once bricked it appears as an unknown device (hardware ID says USB/UNKNOWN) with USB PID 0000 and VID 0000, and further communication with it is not possible.

In your case your system may have updated drivers and during this update (before the device loaded its firmware) it somehow bricked the card. Rebooting into Mac OS (or Ubuntu) unbricked the card by loading the correct firmware on it (Mac and Linux have a different way of detecting USB devices and they somehow manage to detect a bricked card, where Windows just says "unknown device"), so it appears again using the correct USB PIDs & VIDs and Windows can load the correct driver (and firmware) for it.

Related question with a more detailed answer of mine for future readers trying to make this card work on Windows machines.