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  1. #1
    iMac 27 2012 not detecting Thunderbolt display
    Hello,

    i am using a 2012 27 inch iMac, the first slimline model. Now i have purchased a second hand 2011 27 inch display to use as second monitor. No matter what i do i can't get the iMac ot find it. I have done the shut down, unplug, wait 5 minutes start up again things and also the nvram reset without any success. When i connect it to a 2012 macbook pro it instantly powers up. Any suggestions what else to try? Mac os is Mojave

  2. #2
    iMac 27 2012 not detecting Thunderbolt display
    ferrarr's Avatar
    Member Since
    May 21, 2012
    Location
    Pawtucket, RI, US
    Posts
    6,221
    Your Mac's Specs
    L2014 Mac mini macOS 14, iPhone 8+ iOS 12, 12.9" iPad Pro 1 iOS 12, Pencil 1
    -- Bob --
    Please backup. Everything has a life cycle, unexpected and warning free. Nothing will last as long as you want it to.

  3. #3
    Quote Originally Posted by ferrarr View Post
    I thought that's what i did with unplugging it and waiting? Or is there another way? This is what apple says

    Follow these steps for iMac, Mac mini, Mac Pro, and Xserve.

    Choose Apple menu > Shut Down.
    After your Mac shuts down, unplug the power cord.
    Wait 15 seconds.
    Plug the power cord back in.
    Wait 5 seconds, then press the power button again to turn on your Mac.

  4. #4
    iMac 27 2012 not detecting Thunderbolt display
    IWT's Avatar
    Member Since
    Jan 23, 2009
    Location
    Born in Scotland, Worked in Scotland then England, Now live in Wales
    Posts
    5,532
    Your Mac's Specs
    Late 2015 5K 27-inch Retina iMac, 4GHz i7, 32GB RAM, 1TB Flash Drive, macOS High Sierra 10.13.6
    You sometimes have to do the SMC reset several times, dosada.

    Don't know why, but most of us have found this to be the case.

    May I ask if the "successful" 2012 MacBookPro is also running macOS Mojave?

    Ian
    Ian

  5. #5
    Quote Originally Posted by IWT View Post
    You sometimes have to do the SMC reset several times, dosada.

    Don't know why, but most of us have found this to be the case.

    May I ask if the "successful" 2012 MacBookPro is also running macOS Mojave?

    Ian
    Yes, exactly the same OS version. Do you think installing High Sierra would help?

  6. #6
    iMac 27 2012 not detecting Thunderbolt display
    chscag's Avatar
    Member Since
    Jan 23, 2008
    Location
    Keller, Texas
    Posts
    57,882
    Your Mac's Specs
    2017 27" iMac, 10.5" iPad Pro, iPhone 7+, iPhone 8, Numerous iPods, Mojave
    How are you trying to access the 2011 27" TB display from your 2012 27" iMac? What cables and/or adapters are you using?

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