HT4049: Apple Computers and Displays: Powering peripherals through USBLearn about Apple Computers and Displays: Powering peripherals through USB
nothing plugged into the mac book
You previously stated:
this happens ever time i turn on the computer andno i dont have anything plugged into the usb
When you get the usb error message, you are now saying no devices including the usb hub are connected to your MBP?iMac (3.2 GHz, Intel Core i5-2013), OS X Mountain Lion (10.8.3), Fusion Drive-3.12TB, 32GB RAM
- Shut down the computer.
- Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
- On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
- Release all the keys and the power button at the same time.
- Press the power button to turn on the computer.
Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.
System Management Controller Reset