System Freezes on connecting External Display

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Level 1

19 points

System Freezes on connecting External Display

I just bought a MacBook Pro 13" mid 2012 version since I'm starting to travel a lot. I do a lot of coding on my main PC. I didn't mind having a smaller screen and non retina since i was going to hook it up to my 27" HD monitor for the majority of my work. Here's the problem...

One of two things happen when I try to hook it up via the Apple Thunderbolt to VGA connector. Either

1. The external display pops on but at the MBP 2012 native resolution (1200 x 800) and I can't change it at all

or

2. The entire system grays out and locks up and the second monitor shuts itself off saying there is no input. Then I have to hold down the power button to completely shut it down.

Nothing is wrong with the display or the adapter as I've tested them both on another laptop my wife has and my main development desktop (both PC). I'm assuming something is wrong with the MacBook or the underlying software. I'm running El Capitan and the MBP is maxed out in RAM and has a 500 GB SSD. I tried a bunch of things I saw online already but none of them worked. Is there anything I can do to get the 2nd display to work at its 1920 x 1080 resolution?

MacBook Pro (13-inch Mid 2012), OS X El Capitan (10.11.4)

Posted on Mar 31, 2016 3:30 PM

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Answer 1

Mar 31, 2016 3:47 PM in response to drebux

Have you tried a PRAM reset?

How to Reset NVRAM on your Mac - Apple Support

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Answer 2

drebux Author

Level 1

19 points

Mar 31, 2016 3:51 PM in response to Eustace Mendis

That was the first thing I tried. It didn't do anything. This Mac is literally 2 days old, I just got the adapter in the mail today and have been messing with it for a few hours.

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Answer 3

Mar 31, 2016 4:31 PM in response to drebux

Apple menu / System Preferences / Displays.

What have you selected?

Scaled gives you some control of the screen resolution, default for display is determined by the external monitor.

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Answer 4

drebux Author

Level 1

19 points

Mar 31, 2016 5:08 PM in response to Eustace Mendis

if I choose default its only the 1200x800 resolution. If I choose scale and select any of them my system freezes. If I try the option or alt trick I saw it lists all the other resolutions I'd want, but they still freeze my computer if I select them. Also when I turn on my computer if I have the mini dp to vga hooked in already my MacBook won't even get to the logon screen before stalling out. I've never had an issue like this with any other system I've run.

I'm out of ideas so thank you to anyone who has some workaround for this.

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Answer 5

Apr 1, 2016 7:54 AM in response to drebux

Do you have another adapter you could try?

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Answer 6

drebux Author

Level 1

19 points

Apr 1, 2016 8:34 AM in response to Eustace Mendis

I ordered another one that is dvi-d to try. It'll be here Tuesday. I don't have an Apple Store within 2 hours of me.

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Answer 7

Apr 1, 2016 8:39 AM in response to drebux

If [√] Mirror Displays is checked, BOTH displays are forced to the "lowest common denominator" resolution that both appear to be capable of.

To set the resolutions separately, uncheck that box.

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Answer 8

drebux Author

Level 1

19 points

Apr 1, 2016 9:53 AM in response to Grant Bennet-Alder

I unchecked that first time around, there's no point in mirroring a display for what I do, it didn't make a difference. I run 3 displays on my PC and it's never been an issue. This is my first Mac however. Searching the Internet I've realized I'm not the only one having these issues. I'll keep trying things for the next week but if it doesn't resolve itself I'll just have to return it. It's impractical to code on a 13" display while at home.

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Answer 9

Apr 1, 2016 3:55 PM in response to drebux

i have the same problem, i play videos on a screen, those videos get freeze, i have the same thunderbolt, i dont know what to do. looking everywhere to solve the problem 😟

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Answer 10

drebux Author

Level 1

19 points

Apr 4, 2016 2:50 PM in response to Grant Bennet-Alder

New adapter came in. It's the MiniDP to DVI. My system no longer crashes, yay. However I now have a new problem. The display settings allows me to choose the 1920x1080 native resolution yet my screen has two black bars along either side of the screen. Not only that the resolution is atrocious for an HD monitor. It has vertical lines that run throughout the screen. Any ideas guys and gals? I didn't think adding an external monitor would be rocket science for a Mac. Guess I was wrong. The picture I posted is bright so you can see the black bar I'm talking about on the right side of the screen. It also appears on the left. That's the first issue I'd like to tackle. After that I need to figure out why the screen resolution isnt very good but on my PC and Linux system it's perfectly fine.

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Answer 11

Apr 4, 2016 4:38 PM in response to drebux

Do you have a manual for the 27" monitor? I would start there, verifying that the monitor settings are correct to accept and display the signal you are feeding it. (With my Acer monitor there were a few steps - on the monitor - to find the correct configuration.) Fortunately this only has to be done once.

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Answer 12

ReeLeis

Level 1

4 points

Aug 31, 2016 2:16 PM in response to drebux

It sounds like you got your main question taken care of with a hardware fix, but in case others have the same problem and a new adapter doesn't work, I had to boot into safe mode and then plug the monitor in. This worked, and then when I restarted regularly I was able to use the external monitor again.

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Answer 13

Oct 12, 2016 1:24 PM in response to drebux

Not sure if this will help you or others with this issue, but I was going crazy with my 2016 macbook pro retina hanging when connecting my Dell 4k 32" monitor. I would have to hard reboot it every time the issue occurred (which was about once every couple days.

What I did that has caused me to not have the issue for about 2 weeks now is I stopped using any 3rd party apps (like RDM) that allowed me to crank up the resolution on my macbook beyond the maximum allowed in settings. By keeping my macbook at a resolution allowed in MacOS settings (I use Display Resolution "Scaled" and "More Space"), it seems to have cleared the issue for me. On my 15" Retina, Scaled with More Space = 1920 x 1200. I wish Apple supported higher resolutions on Macbook Pro Retina.

While I don't like working at the lower 1920 x 1200 resolution, I'd rather use that resolution to prevent the hangs.

Hopefully this helps others.

Regards,
Jason

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