El Capitan unstable when connecting to external monitor using DisplayPort

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Level 1

19 points

El Capitan unstable when connecting to external monitor using DisplayPort

I have a MacBook Pro Retina 15" mid-2015, 2.8 Ghz Intel Core i7, 16Gb RAM running MacOS 10.11. The external monitor is an Asus MX299Q.

Before El Capitan I did not have this issue.

When I connect the external monitor via Display Port - that is my preference - the photos below show what I see. The photos are from three different attempts. Apparently the same does not happen using HDMI. The issue happens:

- when I turn off the external monitor and turn it on again, and

- when I connect the external monitor after using the laptop's own display

I would like to quickly understand if it is a hardware or a software problem, so that at least I know where to go next. The way the issue started with El Capitan suggests the latter. Thanks.

Giacecco

If I detach the external monitor and try to use the laptop's display, two times the display was ok but the system was unstable and I could slowly manage to close all applications and restart. Once, though, the problem was still there, as you see here, and I had to force turn-off and on again:

MacBook Pro with Retina display, OS X El Capitan (10.11), 15-inch, mid-2015, 16Gb RAM

Posted on Oct 4, 2015 12:09 AM

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Answer 1

Best reply

sterling r

Community Specialist

Oct 13, 2015 12:19 AM in response to Giacecco

Hello there Giacecco,

It looks like you're seeing some unexpected graphical anomalies between your internal and external displays. I would suggest the troubleshooting in the following article to help you troubleshoot this issue:

Apple computers: Troubleshooting issues with video on internal or external displays

This section in particular:

If more than one video adapter is in use (or "daisy-chained"), troubleshoot by using only one adapter.
Example: A mini DisplayPort to DVI adapter connected to a DVI to HDMI adapter is an unsupported configuration because there is a series of adapters in use.

If available, try using a different display and or adapter (or use a different connector by using DVI instead of VGA, for instance).

Reset the system

You can reset the Mac's parameter RAM and SMC.

Reset the resolution

Start up in Safe Mode.

From the Apple () menu, choose System Preferences.

Choose Displays from the View menu to open the preferences pane.

Select any resolution and refresh rate that your display supports.

Restart your computer.

Thank you for using Apple Support Communities.

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Answer 2

Atigon

Level 1

0 points

Oct 8, 2015 8:52 AM in response to sterling r

This works fine

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Answer 3

Giacecco Author

Level 1

19 points

Oct 13, 2015 12:21 AM in response to sterling r

A quick update to share that the PRAM reset did not solve the problem and the problem is still there, identical to how I described it originally.

Resetting the resolution also seems not to be applicable, as I can use the Mac perfectly after rebooting, as long as I don't connect the external display straight away. I am sorry I forgot to write this the first time.

I did not try the SMC reset but, from the instructions, it sounds a bit worrying and I cannot afford losing more time if anything went wrong with the Mac I use every day for work.

Someone knows if Apple monitors this forum or I need to create a ticket with them, too? Thanks.

Giacecco

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Answer 4

sterling r

Community Specialist

Oct 13, 2015 11:09 AM in response to Giacecco

If the troubleshooting didn't work for you, then I would next contact Apple. You may need to take it into a store for further evaluation:

MacBook Pro - Contact Support - Apple Support

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Answer 5

Eric Root

Level 10

684,039 points

Oct 16, 2015 12:09 AM in response to Giacecco

Apple doesn’t routinely monitor the discussions. These are mostly user to user discussions.

Send Apple feedback. They won't answer, but at least will know there is a problem. If enough people send feedback, it may get the problem solved sooner.

Feedback

Mail Feedback

Or you can use your Apple ID to register with this site and go the Apple BugReporter. Supposedly you will get an answer if you submit feedback.

Feedback via Apple Developer

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Answer 6

cugms

Level 1

5 points

Oct 14, 2015 7:55 PM in response to Giacecco

I have the same issue on my 2015 15" Retina Macbook Pro after upgrading to 10.11 (El Capitan). The problem did not exist with 10.10. So I would say it is highly unlikely that you have a hardware problem since both of us started seeing this only after "upgrading".

I'll contact Apple also to report this.

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Answer 7

jimbojsb

Level 1

0 points

Oct 15, 2015 7:14 PM in response to Giacecco

Having this exact problem. What I have narrowed it down to is the Iris graphics. This -never- happens when using the hardware GPU. For me, the workaround is to open Photoshop before connecting a display, as that forces a GPU switchover to the AMD system.

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Answer 8

cugms

Level 1

5 points

Oct 15, 2015 8:06 PM in response to jimbojsb

Good find, jimbojsb. Since you've narrowed it down to Iris, I suspect unchecking the "Automatic graphics switching" option in the Energy Saver system preferences may be another way to work-around the issue. This option applies to both Battery and Power Adapter cases, so unfortunately, if this works, it may come with a sacrifice to battery life. I'll report back once I've determined if this works or not.

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Answer 9

Giacecco Author

Level 1

19 points

Oct 16, 2015 12:10 AM in response to jimbojsb

Thanks jimbojsb, I had tried that but it did not change the situation for me.

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Answer 10

Giacecco Author

Level 1

19 points

Oct 16, 2015 12:13 AM in response to Giacecco

I've contacted Apple and - as sterling r suggested - they insisted that I tried an SMC reset. Did that, and so far so good, the problem did not happen again, but I think it is too early to celebrate. Something I've noticed, too, is that the external display appears to "wake up faster".

Moreover, I've stopped having a secondary, minor issue, that is that sometimes the external display did not realise I had connected it to the Mac, and I had to switch thunderbolt port to wake it up.

I'll keep you posted.

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Answer 11

cugms

Level 1

5 points

Oct 19, 2015 9:41 AM in response to cugms

I haven't had the issue since unchecking the "Automatic graphics switching" option as described in my previous post. This is only a workaround, though, since it may be preferable to use automatic graphics switching.

I have not yet tried the SMC reset.

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Answer 12

cugms

Level 1

5 points

Oct 19, 2015 11:13 AM in response to cugms

Scratch that. Just had the scrambled external display issue even with "Automatic graphics switching" disabled. Problem occurred when waking macbook. It does seem to be less frequent than when Automatic graphics switching is enabled, though. Trying SMC reset next.

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Answer 13

cugms

Level 1

5 points

Oct 19, 2015 12:48 PM in response to cugms

Resetting SMC did not solve problem either. I followed the instructions here. I haven't found a description of how to verify the SMC was indeed reset, though.

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Answer 14

Giacecco Author

Level 1

19 points

Oct 20, 2015 7:01 AM in response to Giacecco

Unfortunately the issue was never gone, it was just by chance that it did not happen in the hours immediately following the SMC reset. So the SMC reset is *not* the solution.

Some workaround that I am testing at the moment is the following sequence: a) wake up the laptop just before you need to connect it to the external monitor, then quickly b) close the lid and c) connect the monitor.

For cugms: I had tried disabling "Automatic graphics switching", too, it's not the solution.

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Answer 15

Oct 21, 2015 1:19 AM in response to Giacecco

I have the same issue with my 2015 MacBook Pro. I always have graphics card switching off so that doesn't solve it. It only seems to happen on my dell 4k monitor at home, my dell 23" at work has not shown the issue yet. It is very random for me.

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