Graphic Designer Tip: Bluetooth Not Available on Mac

I keep having my Bluetooth icon on my map get "disabled"

As a Graphic Designer and Website Designer using a Mac, I have encountered this problem multiple times on my newer iMac: when I click on my Bluetooth icon in my Mac's main menu (top right), it is greyed out and says "Bluetooth Not Available" when I click on it. It won't let me turn it on or off or do anything with it. I tried some various troubleshooting techniques I foudn by Googling "Bluetooth Not Available on Mac" but none of them worked (such as deleting my Preferences plist Bluetooth file, restarting).

So I called Apple at 800-692-7753 and their tech support provided the answer:

Unplug all your USB items, and restart computer.

This was the only thing that worked! I unplugged all my USB connections including my keyboard, so I had to use the on/off button on the back of my IMac to restart the computer without a keyboard (which was USB wired). Make sure that all your files and programs are closed so it doesn't prompt you to close files or programswhen using the on/off switch on the back. After restarting, then re-plug the USBs back in. This fixed it so my Bluetooth is back on! I'm not sure why this works, but apparently sometimes the Bluetooth can conflict with USB connections, so unplugging all the USB items and restarting will fix your problem.