I plugged in a Dell USB mouse into my MacBook so that I could take a break from using the track pad. Then I rebooted the laptop and now it will not boot up. Booting in Verbose Mode shows the following:
USBF: 32.922 [0X9AD1D001] The IOSBFamily is having trouble enumerating a USB device that has been plugged in. It will keep retrying. (Port 4 of Hub at 0x24000000).
Still waiting for root device
It just keeps looping back to "Still waiting for root device" error message even though I have completely unplugged the USB mouse.