Q: mac mini usb port not working

Hi, hopefully you still have AppleCare on it, I think it needs taking in, but long shot...

reset FW bus, same goes for USB reset...

Reset the Firewire bus

If your Firewire or USB isn't recognizing any device.  A solution which has worked for some whose hard drive became invisible in 10.4 was simply to follow these four steps to reset the Firewire/USB bus:

1. Shut the machine down.

2. UNPLUG the power lead to the computer and any firewire/USB drive or devices.

3. leave it for 10 minutes.

4. Connect back up and reboot.

http://www.macmaps.com/firewirebug2.html

Mine did this too a few weeks ago. Lost mouse and keyboard on reboot.

Resetting the PRAM brings it all back.

Hold the CMD+Option+P+R keys when you boot and wait till the Startup chime sounds three times, then release the keys.

This worked!!! Nice!!! I had one "dead" USB port on my 2012 Mac mini and resetting the PRAM did the trick! Thanks so much!

Thanks.... Followed your instructions and it resolved my USB problem...

I had a Logitech C920 webcam that was getting power (blue LED indicators coming on when camera should've been in use) but not picking up any sound or video while plugged into one of my 2012 Mac Mini's USB ports. When I plugged the webcam into one of the USB ports on the side of my Apple USB keyboard (which is, in turn, plugged into a different USB port on the Mac Mini), it worked correctly.

Rebooting & resetting PRAM did the trick - the webcam now works perfectly while plugged back into the Mac Mini.