5 Replies Latest reply: Mar 11, 2013 7:51 AM by lilitesq
aefron3 Level 1 Level 1 (0 points)

I just purchased a new iMac (2.7 GHz Intel Core i5) and (to my immense frustration) I am unable to use the external display (ViewSonic VG2030wm) that worked very well with my previous iMac. Following Apple's instructions, I am using a Mini DisplayPort to DVI Adapter that I connected to the Thunderbolt port of my new iMac.

My new iMac doesn't recognize the external display.

What's wrong?

iMac, Mac OS X (10.6.7)
  • 1. Re: external monitor
    Rick Lang Level 4 Level 4 (1,230 points)

    Apple’s web pages imply you should not have a problem:


    "High performance on display.

    Thunderbolt I/O technology provides native support for Mini DisplayPort displays. It also supports DisplayPort, DVI, HDMI, and VGA displays through the use of existing adapters. So you can connect your Apple LED Cinema Display or other existing display, along with multiple high-speed devices, all from a single port.”

    Have you called Apple?  You have at least 90 days telephone support for problems you are experiencing.


    What brand is the mini-Displayport to DVI connector you are using?  Was it purchased through the Apple Store?

  • 2. Re: external monitor
    aefron3 Level 1 Level 1 (0 points)

    I have called and talked to Apple many times. Nobody seems to have a clue about my problem. They are basically telling me that my external monitor is too old (about 7 years). I don't believe that.


    I was using an Apple adapter purchased (and now refunded) at an Apple store.

  • 3. Re: external monitor
    sandspider Level 1 Level 1 (0 points)

    It amazes me that Apple has not confessed.  I purchased an new 2011 imac last month and had flickering issues with my external 24" imac display (1 year old).  After discussion with apple support, I replaced the machine.  The second machine also had the same problem.  Apple then requested that I bring both computer and 2nd monitor into the store for them to trouble shoot.  The frustrating thing is they never took it out of the box and said that there is a problem with the thunderbolt port on all new 2011 imac computers.  The situation was shaddy and felt secretive, meanwhile right beside me other people are by the new computers.  I returned the computer on the spot and will wait until this issues is resolved.  I am suppose to get a call when the issue is resolved.  I am still waiting....

  • 4. Re: external monitor
    coolkid99 Level 1 Level 1 (0 points)

    Not just a problem with the thunderbolt port, my brand new mini mac(Lion) only sees the main monitor half the time. Linked through the hmidi. So sometimes fine other times everything rearranged to the second monitor after a wake up. Only sleeps and wake ups seem to randomly trigger the main monitor back to life. Tried posting the problem here and have seen other people with the same issue, so far no one seems to have received any solution or even acknowledgement from apple that this issue exists. Been a couple of months now since I first posted and it is very poor.
    Come on apple do you have anything to say on the problem?

  • 5. Re: external monitor
    lilitesq Level 1 Level 1 (0 points)

    i have the same problem

    no external monitor recognition !!!