OS X Mountain Lion: Check your device’s Thunderbolt connection
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If a Thunderbolt device isn’t working properly, it might not be properly connected to your computer.
- Connect another device to your Thunderbolt port on your Mac. If you can’t use that device, restart your Mac. If you still can’t use a device with the port, your computer may need to be repaired.
Find out how to service or repair your Mac
- If more than one device is connected to the Thunderbolt port on your Mac, disconnect all other devices. Connect the device directly to the computer without using extension cords.
- If you can use your device now, there may be a problem with one of the other devices. Try reconnecting the other devices and extension cords to your computer, one by one. When you find the device causing the problem, review its documentation for further troubleshooting steps.
Last Modified: Sep 4, 2015