10.6.7 breaks external monitor support

Question

10.6.7 breaks external monitor support

I'm using a Samsung SBX2440 LCD monitor (1920x1080) on a Macbook Pro 17" 2011.
Before applying the 10.6.7 update, it worked fine going mDP->HDMI->DVI. Afterwords,
the Mac recognizes it and acts as if it's connected, but the monitor does not think it is
(says check cable). I've tried:

- Removing com.apple.windowserver plists.
- SMC reset
- PRAM reset
- Different cables
- Different mDP adaptors
- Reapplied 10.6.7 update
- SwitchResX
- Disconnecting power to the monitor for an hour

Nothing works.

On my old laptop, a ~2009 13" MBP running 10.6.7 with the same cables and adaptors,
the monitor works fine. So something changed in 10.6.7, and not for the better.

Macbook Pro 17" 2011, Mac OS X (10.6.7)

Posted on Mar 24, 2011 4:38 PM

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Answer 1

ad1815

Level 1

0 points

Mar 25, 2011 2:24 AM in response to stoneymonster

I have the same problem after upgrading to 10.6.7. It worked perfect before the upgrade. My monitor is SyncMaster 205bw via VGA.

When the external monitor is connected, things work as usual for the first few minuts, then it blacks out and then both internal and external monitor becomes blue. It recovers itself after a while, and then it happen again.

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Answer 2

Mar 25, 2011 2:52 PM in response to ad1815

Taking HDMI out of the equation and going mDP->DVI works fine. So something about
the HDMI to DVI conversion is wonky.

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Answer 3

Csound1

Level 9

59,973 points

Mar 25, 2011 3:07 PM in response to stoneymonster

Are you using 3rd party or Apple cables?

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Answer 4

Mar 25, 2011 3:35 PM in response to Csound1

i'm using Apple cables. And going from Mini-DVI to DVI. And I have the same issue.

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Answer 5

Csound1

Level 9

59,973 points

Mar 25, 2011 4:18 PM in response to Stephen Cox

I had a issue going from mdp-dvi, I changed my mdp/dvi adaptor to an apple branded one and the issue resolved itself; but as you are already there I have no further input.

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Answer 6

Mar 27, 2011 3:52 PM in response to stoneymonster

Hi,

I have been having the same issues with post 10.6.4 breaking my second monitor support (iMac 27" 2010 REV (iMac11,3, Intel Core i3, ATI Radeon HD 5670)).

NOT Working: Moshi Mini DisplayPort HDMI adapter to HDMI to DVI to Samsung SynchMaster 2433. Display Preferences sees the monitor but no picture shows up on the external monitor.

WORKING: Apple Mini DisplayPort DVI adapter to DVI to Samsung SynchMaster 2433. 10.6.7

Obviously not ideal that I needed to buy a $35 adapter and a very expensive DVI cable to test.

Bug report to Apple updated and submitted to the engineering team.

Message was edited by: airhead75/5

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Answer 7

Mar 27, 2011 5:29 PM in response to stoneymonster

Same problem here. External Samsung SyncMasterP2070 worked fine until 10.6.7. Now it's black.

Ugh.

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Answer 8

ad1815

Level 1

0 points

Mar 28, 2011 5:31 AM in response to ad1815

My problem is not happening all the time. It has not happened today.

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Answer 9

Mar 28, 2011 8:02 AM in response to stoneymonster

Same problem.

Non-apple MiniDP -> DVI works on my Dell 22" with 10.6.6

Not on 10.6.7. Mac thinks screen is connected, but display in black.

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Answer 10

Mar 29, 2011 12:23 PM in response to stoneymonster

Seemed okay today. Maybe just needed a reboot!?

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Answer 11

rturnr

Level 1

4 points

Apr 5, 2011 8:15 PM in response to stoneymonster

I have a display port to d-sub and it isn't working on my 24" Benq.

Monitor just stays blank.

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Answer 12

rturnr

Level 1

4 points

Apr 5, 2011 8:15 PM in response to rturnr

Sorry, this is when running Windows 7 via Bootcamp. Works when running Mac OS.

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Answer 13

Jun 20, 2011 2:18 PM in response to stoneymonster

For anyone still struggling with this, as I was for a couple of hours today, I found a really simple fix:

Despite using it without problems in earlier OSX versions, in 10.6.7 I couldn't get my samsung syncmaster to run at native (i.e. highest) resolution. I became curious when I saw in the system profiler that there are two graphics cards/drivers (strange I'd never paid attention to this before). So I wanted to switch to the NVIDIA GeForce

9600 and found out that the way to do this was simply by going to Sys Prefs->Energy Saver and setting Graphics to Higher Performance. Monitor performance perfect thereafter.

All the best, Michael

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Answer 14

Jan 9, 2012 5:02 AM in response to stoneymonster

Michael, you're a genius!!

I have an 15inch MacBook Pro that I've just installed Snow Leopard 10.6.3 on.

Prior to this install, I've had it hooked up to my Samsung SyncMaster 2243 via an Apple MDP/VGA adapter and a third party VGA cable. It has been flashing on and off a black screen every now and then for the past 2 years and I googled that it was just a crappy communication between the MBP and the Samsung... but now since installing 10.6.3, the Samsung display just flashes the desktop for a second then turns black for good - occationally flashing analogue/digtal prompt display. Tried everything for hours. Nothing worked, thought I was gonna have to buy a new all Apple VGA lead then came across Michael's above solution. Tried it and it worked IMMEDIATLY!!! And the monitor doesn't flash black anymore AT ALL!! Whoo-hoo!! Thanks heaps.

WHAT TO DO TO FIX:

Go to => System Preferences => Energy Saver => change graphic settings to Higher Performace.

Cheers!!

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Answer 15

Jan 9, 2012 5:02 AM in response to mdedwards2

Cheers mate. Changing the graphic settings fixed everything!!!

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