User profile for user: adieknight
adieknight Author
User level: Level 1
9 points

Target Display - Black Screen

I have a MacBook Pro (new-ish model with Thunderbolt 3) and a desktop Mac (late 2014 model) which I want to use as a 'monitor' for the MacBook. I have a thunderbolt 2 cable and tb2->3 converter in to the Macbook.


When I hit Command F2 on the destination (Desktop Mac) both screens just go black and nothing happens. I've tried different cables but the same issues.


I've resorted to screen sharing the Macbook but this is quite clunky and not a great long term solution.


Any help would be much appreciated,


Thanks!

Posted on May 1, 2018 8:43 AM

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User profile for user: raina_b22
raina_b22
User level: Community Specialist

Posted on May 2, 2018 6:23 AM

Hello adieknight,

Thanks for reaching out to the Apple Support Communities. I understand you've had some trouble using Target Display Mode, and I have some information that may help.

Have a look at the excerpt from the article below for some helpful troubleshooting steps.

Use your iMac as a display with Target Display Mode - Apple Support

If Command-F2 doesn't work

If your iMac doesn't switch to Target Display Mode when you press Command-F2, check these things:

  • Make sure that the iMac you're trying to use as a display supports Target Display Mode.
  • Target Display Mode works only when your primary Mac is logged in to a macOS user account. For example, if your first Mac is at the FileVault login screen, pressing Command-F2 on your iMac does not enable Target Display Mode. You must first log in to your Mac (using a regular display, if necessary) before you can use an iMac in Target Display Mode.
  • Make sure that you're pressing Command-F2 on the keyboard that's connected to the iMac you want to use as a display.
  • In Keyboard System Preferences, if the checkbox is enabled for "Use all F1, F2, etc. keys as standard function keys," the key combination changes to Command-Fn-F2.
  • Make sure that your Mini DisplayPort or Thunderbolt cable is connected to both computers.
  • If you're currently logged in on the iMac you want to use as a display, try logging out to return to the login window. Then press Command-F2 again.
  • Some older Apple keyboards and third-party keyboards might not allow Command-F2 to toggle display modes. If this happens, use the keyboard that came with your iMac to toggle Target Display Mode on and off.
  • If your iMac is currently started up in Windows, it won't enter Target Display Mode. Target Display Mode isn't supported in Boot Camp.



If you run into any trouble, please reach out again.
​Best Regards.
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Question marked as Top-ranking reply
User profile for user: raina_b22
raina_b22
User level: Community Specialist

May 2, 2018 6:23 AM in response to adieknight

Hello adieknight,

Thanks for reaching out to the Apple Support Communities. I understand you've had some trouble using Target Display Mode, and I have some information that may help.

Have a look at the excerpt from the article below for some helpful troubleshooting steps.

Use your iMac as a display with Target Display Mode - Apple Support

If Command-F2 doesn't work

If your iMac doesn't switch to Target Display Mode when you press Command-F2, check these things:

  • Make sure that the iMac you're trying to use as a display supports Target Display Mode.
  • Target Display Mode works only when your primary Mac is logged in to a macOS user account. For example, if your first Mac is at the FileVault login screen, pressing Command-F2 on your iMac does not enable Target Display Mode. You must first log in to your Mac (using a regular display, if necessary) before you can use an iMac in Target Display Mode.
  • Make sure that you're pressing Command-F2 on the keyboard that's connected to the iMac you want to use as a display.
  • In Keyboard System Preferences, if the checkbox is enabled for "Use all F1, F2, etc. keys as standard function keys," the key combination changes to Command-Fn-F2.
  • Make sure that your Mini DisplayPort or Thunderbolt cable is connected to both computers.
  • If you're currently logged in on the iMac you want to use as a display, try logging out to return to the login window. Then press Command-F2 again.
  • Some older Apple keyboards and third-party keyboards might not allow Command-F2 to toggle display modes. If this happens, use the keyboard that came with your iMac to toggle Target Display Mode on and off.
  • If your iMac is currently started up in Windows, it won't enter Target Display Mode. Target Display Mode isn't supported in Boot Camp.



If you run into any trouble, please reach out again.
​Best Regards.
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Target Display - Black Screen

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