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Here is the situation:

My macbook hard crashes (basically appears to turn off) when I plug in my VGA out dongle.

I have looked through the logs and cannot find any related logging.

The VGA display device (i.e. LG LCD display) was on at the time and the VGA signal is routed through a Belkin KVM device, although I have had the same behaviour without the KVM device too.

To make the situation even more difficult to figure out it does not occur every time I connect the dongle, in fact it is relatively rare, probably no more than once a week.

Here are my other specs:

MacBook Pro 15 in Purchased December 2008 OS X 10.5.8

Has anyone else seen this type of behaviour before? Any suggestions on what might be the cause?

share|improve this question
Does it crash if you boot the computer with the dongle inserted? – Hello71 Aug 22 '10 at 22:02
When it "crashes" are you still able to access the computer (eg. ping or control remotely)? Does it change when unplug it? Additionally are you forced to restart the computer (a hard lock) or is the computer itself turned off (most likely a power issue) – Chealion Aug 22 '10 at 22:35
@Chealion No - when it crashes, it is like it is turned totally off and no change when I plug/unplug it. Yes - when this happens as far as I can tell I have to turn the computer on from scratch (i.e. use the power button to boot it up) – dtlussier Aug 22 '10 at 23:16
@Hello71 No - I've never had a problem booting up with the dongle inserted. The problem appears only when I put the dongle into the machine while it is running. – dtlussier Aug 22 '10 at 23:17
Thanks! That clarifies things a lot. TuxRug's answer is a good next step. – Chealion Aug 23 '10 at 4:24
up vote 5 down vote accepted

It sounds like it could be a short in either the monitor, the dongle, or the notebook. If it was a software issue, it should leave a log, and it wouldn't just turn off, it'd more likely reboot.

First try some things from the User's Manual:

  • Update your system software.
  • Run hardware diagnostics
    1. Shutdown the computer
    2. Unplug ALL devices and cables from the computer except for the power cord.
    3. Boot up the computer while holding the D key.
    4. Select your language, then press ENTER.
    5. After about 45 seconds, the 'Apple Hardware Test' will appear. Follow the directions on the screen.
  • Reset your PRAM
    1. Shut down your computer.
    2. Boot up the computer while holding Command+Option+P+R until you hear a second startup chime.

If none of that works, try these ideas:

  • To test if it's a software issue, plug in the monitor with the laptop turned off. Try turning on the computer. If it turns off right away or does not turn on at all, it's a hardware issue. If it boots up partially before crashing, or boots completely without crashing, it's probably a software issue and you might have to re-install OSX.

  • If you determine it's a hardware issue, try plugging in the dongle with the monitor disconnected from it. If it crashes, it's either the dongle or the laptop. Try to find another dongle to test with. If you borrow a dongle from a friend or buy a new dongle and that crashes it too, then there's a short in the laptop.

  • If the dongle by itself doesn't crash the computer, then connect the monitor with the power to the monitor disconnected. Plug the power into the monitor. Then, turn on the monitor. If it crashes during any of these steps, then it might be the monitor. Try another monitor to test with the system.

share|improve this answer
I'll run through these steps and report back. Thanks! – dtlussier Aug 22 '10 at 23:17
I've done the hardware test and reset the PRAM. All seems well for now, and I will try the other iterative tests tomorrow. – dtlussier Aug 23 '10 at 4:56
I have now done all the other iterative tests suggested by TuxRug but unfortunately I haven't been able to recreate a crash in any of the permutations. Thanks for tips though - I'll keep an eye on the problem and hope that it doesn't reappear. – dtlussier Aug 23 '10 at 16:37

It might sound a bit dumb, but what caused the same problem here was the fact I inserted the dongle upside-down.

Try flipping the dongle and see if the problem still occurs.

share|improve this answer
You can't put it in upside down... – Canadian Luke Jul 5 '13 at 19:27
@CanadianLuke given enough force you can – aaaaaa Feb 13 at 19:04

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