Failing at using target display mode on Late 2009 27" iMac (with Retina MBP)

Discussion in 'iMac' started by captainwing, Feb 28, 2015.

  1. captainwing macrumors newbie

    Nov 1, 2010
    Hi all,

    Would love some help.

    I have a retina 15" Macbook Pro (mid 2014) and am attempting to connect it to a 27" iMac (late 2009) in order to use its target display mode. I've connected it with a Mini Displayport to Mini Displayport cable.

    Once connected I am pressing command+F2 on the iMac which makes both screens go black, however it cannot seem to create the required connection for display.

    Is there something that I am missing here?

    Any help you could give would be greatly appreciated.

  2. captainwing thread starter macrumors newbie

    Nov 1, 2010
    Not sure if issues include:

    - Type of Mini Displayport cord (purchased from eBay - not official cord)
    - Assignment of wireless keyboard / mouse
    - Settings in preferences.
  3. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    In order to use target display mode, both Macs must have the same connection (DP to DP or TB to TB).

    It can't be TB to DP or vice versa if I remember correctly.
  4. captainwing thread starter macrumors newbie

    Nov 1, 2010
    I'm using a Mini DP to Mini DP given the input on the iMac
  5. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA
    Good old Apple beat you.

    Your 2014 Mac is TB, even if it looks like mDP.

    That may be the issue.
  6. captainwing thread starter macrumors newbie

    Nov 1, 2010
    The mini displayport cable should work in the thunderbolt slot though shouldn't it? I would have thought the thunderbolt to thunderbolt connection wouldn't have worked for the (Late 2009) iMac?
  7. rkaufmann87 macrumors 68000


    Dec 17, 2009
    Folsom, CA
    Very simple, it will not work. your MBP is designed to work with other Apple computers that have Thunderbolt connections, your 2009 does not have that.
  8. Thrifty1 macrumors regular

    Nov 21, 2009
    You should be able to do this.

    Here is the Apple support document. It shows you use a mini display port cable (which you have). And the source computer can have a thunderbolt port.

    I have connected a MacBook Air with a Thunderbolt port to a late 2009 iMac using the mini display port cable.

    You may need to adjust the resolution on your MacBook to a lower setting. I'm not sure how the retina MacBooks work using target display mode on the late 2009 iMacs.
  9. redheeler macrumors 604


    Oct 17, 2014
    Thunderbolt is backwards compatible with Mini DisplayPort output. I've been able to connect a rMBP to my 27" 2010 iMac without issue, using a Mini DisplayPort to Mini DisplayPort cable.
  10. aggri1 macrumors 6502

    Jul 21, 2010
    As others have noted, this is incorrect, because Thunderbolt (TB) is backwards compatible to DisplayPort (DP). Note that this compatibility goes just one way: TB port CAN output DP, but DP port cannot accept nor output TB.

    My 2011 MBP with Thunderbolt can ouput a DP signal which my 27" 2010 iMac can display. No problems.

    Don't think I can help with your particular issue though sorry. Perhaps check the display resolutions...?

    Cheers, A.
  11. PEBarck macrumors newbie

    Mar 4, 2015

    just yesterday I cloned an iMac 27 (late 2009) unto my new MacBook Pro 15 like you are trying to do. My iMac has a broken graphics card thus it can only be logged in via Safe Boot with its limited functionality. Target mode also still works. I did the following:

    1. Start the iMac into Target mode by holding down the "T" key after the gong.
    2. Plug a FireWire cable into the iMac. Using a FireWire to ThunderBolt adapter, connect the iMac to the MacBook's TB port.
    3. On the MacBook start the Migration Assistant App (in the Utilities Folder).
    4. Follow on-screen instructions. I only cloned the user areas, not the Applications.

    Worked beautifully! All four user accounts came across OK. Their original passwords all worked OK.


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