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Kelly Sill Author

Level 1

12 points

Target/Extended Display Mode Problem on iMacs

I have a late 2012 27" iMac (High Sierra 10.13.6) that I wish to use as a secondary monitor for my new 27" iMac. I have purchased the Thunderbolt 2 cable and the Thunderbolt 3 to Thunderbolt 2 adaptor. I have followed various tutorials to place my secondary monitor in Target Display Mode. When I do, both screens blink black for a second and screen on the 2012 computer stays black. However when entering the Display System Preferences on the new computer, I do have the option to arrange both displays, but just to repeat, I cannot see anything on that secondary display.

Can anyone help me? I don't want my screens to mirror. I want to use my old iMac as an extended display and be able to drag various windows between the two screens.

Thanks!

Kelly

iMac Line (2012 and Later)

Posted on May 25, 2019 11:16 AM

Top-ranking reply

SeaPapp

Level 7

26,486 points

Posted on May 25, 2019 11:46 AM

Try resetting the SMC How to reset the System Management Controller (SMC) on your Mac - Apple Support

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Target/Extended Display Mode Problem on iMacs

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