27" thunderbolt imac target display mode

Discussion in 'iMac' started by kjid, Nov 29, 2011.

  1. kjid macrumors regular

    May 3, 2011
    I recently got a macbook air 11" and wanted to use my 27 inch imac as secondary display. I connected the thunderbolt cable between the two and hit cmd + f2 on the imac. Both screens flashed (light) blue as if it was going to work. But the Imac just came back with its own screen, and the keyboard and trackpad became unresponsive.
    I could remote login to the imac via the macbook to turn it off.

    Does anyone know a fix for these problems? Am I doing it wrong?
  2. rkaufmann87 macrumors 68000


    Dec 17, 2009
    Folsom, CA
    I would think that would work assuming they both have Thunderbolt. If not then give AppleCare a call, you're covered for 90 days from the date of purchase. They can help you straighten it out.
  3. heimbachae macrumors regular


    Aug 1, 2011
    he only said what kind of MBA he has, I'm guessing he might have a pre thunderbolt iMac and thats why the cable isn't working. get a mini displayport cable an try it again OP.
  4. kjid thread starter macrumors regular

    May 3, 2011
    Sorry for the lack of info.

    I've got the 27" 2011 imac with thunderbolt and the 2011 11" macbook air, with thunderbolt ;)

    I'm using a thunderbolt cable to connect the two, and i've done a thunderbolt transfer using target disk mode on my macbook, so the cable and ports work.
  5. kjid thread starter macrumors regular

    May 3, 2011
    I discovered the thunderbolt firmware was outdated on my imac, but after upgrading to the latest version the firmware numbers are still not equal on the imac and macbook.

    Having the latest firmware on both computers i tried again, but the same glitch/bug occured.

    Is there anyone who can confirm it should indeed work?
  6. xav8tor macrumors 6502a

    Mar 30, 2011
    Yes. Your setup should work. This guy tested all the possible combos:


    If it doesn't, cut out the middlemen like us and call Apple. If you are doing things right, you'll get elevated to tier two or higher quickly. Their tech support is one of the reasons I switched to Mac after 25 years of Windows. It is situations like this, not just failed parts, that makes AppleCare worth the price...over and over.
  7. kjid thread starter macrumors regular

    May 3, 2011
    I did a clean install of Lion on my iMac (not just because of this issue, i was planning on doing one anyway) and that fixed the problem.

    I suspect things got messed up when i tried to do target display mode while the iMac wasnt on latest thunderbolt firmware.

    Thanks again for the replies.

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