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Ian J Grant
Level 1 (5 points)

Q: Phantom non existent external monitor on Mac book pro

Hi all, whenever I open my mac book pro, or wake it from sleep, the screen turns blue and it auto-detects a monitor that is not attached - a generic VGA display - the image at the following URL displays when an external monitor is NOT attached:

http://ellington.tvu.ac.uk/images/displays.png

I have to click 'detect displays' between 8 and 14 (sometimes more) times to trigger another detect routine that always changes to reflect the actual state of monitors.

I have a cinema display and when connected to the MBP - on start-up or awaking from sleep, the MBP often fails to detect the connected monitor and yet displays the same display status as above a generic VGA display - click 'detect displays' 8-14 times and it detects the cinema display. Whenever the machine / display sleeps, it seems to be a lottery as to whether the true display status is retained or whether the MBP detects the phantom monitor, blackens the cinema display and requires the (getting very tedious now) detection routine to get back to what's expect. At that point, all windows have resized and shifted position. I've described the problem to several in-store genius's with no obvious answer. I did not do a clean install from Tiger, but wonder if it would've helped.
What do you reckon? Hardware failing or some strange software problem?
Thanks in advance, Ian Grant

Mac Book Pro, Mac OS X (10.5.2), 2.16 ghz

Posted on Mar 6, 2008 2:45 PM

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Ian J Grant

Q: Phantom non existent external monitor on Mac book pro

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  • by neuroanatomist,

    neuroanatomist neuroanatomist Mar 6, 2008 3:50 PM in response to Ian J Grant
    Level 7 (31,694 points)
    Mar 6, 2008 3:50 PM in response to Ian J Grant
    Try resetting the PRAM:

    http://docs.info.apple.com/article.html?artnum=2238

  • by Ian J Grant,

    Ian J Grant Ian J Grant Mar 9, 2008 4:22 AM in response to neuroanatomist
    Level 1 (5 points)
    Mar 9, 2008 4:22 AM in response to neuroanatomist
    Thank you for your response. I have tried resetting the PRAM and no joy. Next sleep / wake cycle saw the MPB spotting the phantom monitor.

    I first asked about this problem Feb 22, 2007 1:27 AM "Mac Book Pro thinks external monitor is attached when it is not " - running Tiger. I hoped Leopard may solve it. Back then:

    "I have tried trashing the following:

    ~/Library/Preferences/com.apple.windowserver.plist
    ~/Library/Preferences/ByHost/com.apple.windowserverXXXX.plist"

    And asked:

    "I also wondered what the function of /System/Library/Displays/Overides is?"

    I have a feeling this could be hardware. Although I have had it checked out in an Apple store.

    Regards, Ian

  • by Kidde,

    Kidde Kidde Mar 13, 2008 9:55 AM in response to Ian J Grant
    Level 1 (0 points)
    Mar 13, 2008 9:55 AM in response to Ian J Grant
    Same problem on my MacBook Pro (10.5.2).

    Also tryed to reset PRAM, didn't help.

    Best regards, Fredrik

  • by dprado,

    dprado dprado Mar 18, 2008 5:44 AM in response to Kidde
    Level 1 (0 points)
    Mar 18, 2008 5:44 AM in response to Kidde
    Same here with a MBP 10.5.2. No matter how many times I click on "detect Displays" nothing changes. If I attach an external monitor, it is not detected, since the phantom monitor is there. Removing the external monitor makes the screen go blue as if it detected the change, but the phantom monitor is still there on the display list. Never seen it happen on Tiger

  • by cal6n,

    cal6n cal6n Apr 22, 2008 8:02 AM in response to Ian J Grant
    Level 2 (265 points)
    Apr 22, 2008 8:02 AM in response to Ian J Grant
    Same problem here. I'm on a 1st gen 2 GHz MBP with a 256 MB ATI X1600. I get it with a 19" widescreen LCD using the Apple DVI/d-sub; my InFocus projector or my Edirol V4 using the Apple DVI/video adapter.

    I can usually solve the issue with a combination of "detect displays"; "gather windows" & "turn on/off mirroring".

    I've tried trashing preferences, reinstalling Tiger and Leopard and, even though I know it's largely voodoo, repairing permissions. Nothing has helped, except only sleeping my machine, not turning it off, and only plugging and unplugging my adapter when my machine is fully awake.

  • by Soonerprod,

    Soonerprod Soonerprod Apr 24, 2008 9:26 PM in response to cal6n
    Level 1 (0 points)
    Apr 24, 2008 9:26 PM in response to cal6n
    The only solution that I have found is to shut down the computer, connect the display, power up the display, press the power key and close the MBP before the chime. This will cause the computer to start up with the external monitor as the main screen.

    Hopefully Apple will come up with a more elegant solution to this problem.

  • by cal6n,

    cal6n cal6n May 30, 2008 7:31 AM in response to Soonerprod
    Level 2 (265 points)
    May 30, 2008 7:31 AM in response to Soonerprod
    Not really a solution as I generally need to use both screens.

    When I'm using a projector, I need the desktop on the MBP screen but, when I'm using an external monitor, I want my desktop on that.

    It must be said, however, that I haven't seen a phantom monitor since 10.5.3 was released a couple of days ago. It's early days yet, though...

  • by cal6n,

    cal6n cal6n May 31, 2008 12:57 PM in response to cal6n
    Level 2 (265 points)
    May 31, 2008 12:57 PM in response to cal6n
    Scratch that last observation. It's just as bad as ever. Maybe even worse...

  • by Matt 32E,

    Matt 32E Matt 32E Jul 23, 2008 8:34 AM in response to Ian J Grant
    Level 1 (0 points)
    Jul 23, 2008 8:34 AM in response to Ian J Grant
    Just piling on with the same issue - just started this morning, with my most recent update being the MobileMe installation for 10.5.4. For what it's worth, the phantom display ("VGA Display") indicated has never been connected to this computer, and an external display hasn't been used in over a year. (It was a Sony LCD Panel connected via a DVI connection.)

    Macbook Pro 15.4-inch, 1.83GHz, 1 GB RAM

  • by MNield,

    MNield MNield Feb 4, 2009 1:45 AM in response to Matt 32E
    Level 1 (0 points)
    Feb 4, 2009 1:45 AM in response to Matt 32E
    Hello,

    Did you ever resolve this issue? I have precisely the same problem; I connected an external display once, about six months back and now my Powerbook (10.5.6) detects the phantom monitor every time. Like you I have tried trashing every related plist file, reset PRAM, NVRAM, OPen Firmware, deleted AppleDisplay.monitorPanels directory and rebooted.

    It is so annoying having the mouse disappear off whatever edge of the screen I configure the phantom monitor to reside.

    Input much appreciated if indeed you fixed it.

    Marc

  • by Antonius Gan,

    Antonius Gan Antonius Gan Mar 27, 2009 3:00 PM in response to MNield
    Level 1 (5 points)
    Mar 27, 2009 3:00 PM in response to MNield
    Has anyone ever resolved this problem?

    Ran into this problem last week, and still haven't been able to find out what happened and how to get rid of the extra "VGA Display".

    I've tried trashing com.apple.preference.displays*.plist, and all the windowserver.plist files, but still the extra monitor is there.

    Message was edited by: Antonius Gan

  • by chip.r,

    chip.r chip.r May 13, 2009 9:14 PM in response to Antonius Gan
    Level 1 (34 points)
    Applications
    May 13, 2009 9:14 PM in response to Antonius Gan
    You can add me to the list of people having the problem. I've had it for some time on my first generation MBP with intermittent frequency. I've searched from time to time to see if there is a solution but no luck. It looks like I'm not alone and this problem seems to be persistent.

    Any thoughts? Is it hardware? Software? I've started to think it may be a hardware short inducing a false detection on the external port.

    Chip

  • by mike_lyman,

    mike_lyman mike_lyman Feb 24, 2010 8:22 PM in response to chip.r
    Level 1 (0 points)
    Feb 24, 2010 8:22 PM in response to chip.r
    Yesterday I found the same problem. I disconnected from a Dell Projector and then later that night I noticed that my computer still showed two monitors. I'm still able to connect to an external monitor and it will detect it. However, immediately after disconnect the phantom display is back.

    A little annoying because I'm always having application windows open on that phantom display.

    Also I noticed that when I plugged into the projector the color was off significantly, as if there was a bad connection. I tried a variety of connectors and connected my laptop to a variety of different external monitors and all of them work flawless except for the Dell Projector. (I didn't try it on another projector because I only have the one.)

    My conclusion is somehow when I disconnected from the projector I hadn't fully shut down or gone to sleep or my computer was in the middle of a disconnect when I closed the lid and this interruption as my computer transitioned from 2 displays to 1 created the phantom display. Hope to see a solution to this.

    Thanks

  • by John Heffernan,

    John Heffernan John Heffernan Apr 7, 2010 7:49 AM in response to mike_lyman
    Level 1 (0 points)
    Apr 7, 2010 7:49 AM in response to mike_lyman
    Seems like a hardware issue. I just started to have it on an iMAC G5, like many others.
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