For the impatient:
sudo /usr/sbin/blued
For the past several weeks the Bluetooth in my MacBook Pro has been acting weird. On an average day the Bluetooth would simply stop working, resulting in a “connection lost” with my Mighty Mouse. I tried resetting the SMU/PMU, zapping the PRAM, moving preferences out, etc. and none of them worked.
Recently I notice my Bluetooth acting weird, displaying a squiggly line though the icon in the menu bar and displaying “Not Available” when clicked. No response from the System Preferences either.
After searching the interwebs, the only results I found were the solutions mentioned above. I then did some research into the Bluetooth daemon itself. After executing the following command from the Terminal:
sudo /usr/sbin/blued
Bluetooth came back to life! No SMU/PMU/PRAM reset or reboot needed. And it has been working fine ever since.
One note — once the Bluetooth starts you will need to press Control-C to exit the command. Don’t worry, the daemon will still be running.