macOS User Guide
- Welcome
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- Work across devices using Continuity
- Use iPhone as a webcam
- Use iPhone with Desk View
- Stream audio and video with AirPlay
- Use one keyboard and mouse to control Mac and iPad
- Hand off between devices
- Unlock your Mac with Apple Watch
- Make and receive phone calls on your Mac
- Sync music, books, and more between devices
- Resources for your Mac
- Resources for your Apple devices
- Copyright
Check your device’s Thunderbolt connection to Mac
If a Thunderbolt device isn’t working properly, it might not be correctly connected to your computer.
Check your Mac: Connect another device to the 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 Mac may need to be serviced. See Find out how to service or repair your Mac.
Check chained devices: Disconnect all devices and cables from your Mac, then connect the device directly to your computer using its cable. If the device functions correctly, there may be a problem with one of the other devices. Try reconnecting the other devices and cables to your Mac, one by one. When you find the device causing the problem, review its documentation for further troubleshooting steps.