Q: El Capitan unstable when connecting to external monitor using DisplayPort

I previously used a 1920x1080 monitor using the mini display port and never had this issue.

Same here with a LG 4K display. I had exactly the same issue on 10.11.4. Now I have upgraded to 10.11.5 beta but it doesn't help.

I'm still having issues with the latest MBP 15 inch mid 2015 - with dedicated GPU. Connected to external Dell 4K monitor Dell P2715Q 27" Ultra HD Monitor.

I'm having less issues with the MBP lid open prior to connecting the monitor but not completely resolved. For example just yesterday my whole laptop froze after letting the computer sleep with the external monitor connected. A good cable improves things but not completely. Its frustrating...

My situation is similar. My old Macbook pro (2012) running the latest OS does not have the issue (happened 4, 5 times in three years). But ever since I got my new macbook pro (2015) with my two DELL 4K monitors, it happens everyday. It barely happens with low resolution monitors I have at home. But every single time with 4K. The OS is fresh installed according to Etrecheck, everything is normal.

Looking for explanation and patches from Apple!

Thanks

It seems like the problems is on the TB - DP cables. none of them on the market properly support sleep / wake up.

Apple needs to make a proper TB to DP cable !

Upgraded to 10.11.5 and the issue persists. I have also tried replacing the cable but it still happens randomly.

When the screen freezes, there are a lot of logs saying: GPU Driver appears to be hung (over 5 continuous seconds of unreadiness)

So it is likely to be an issue in Apple's graphics driver itself. The original post was posted half a year ago, I just can't believe Apple has made the bug go through that many betas again and again!

This seems to be the official advice relating to some of the issues raised in this thread:

Use your Mac notebook computer in closed-display mode with an external display - Apple Support

Ever since I've turned off the sleep feature when plugged into power (and plugged into the external 4K display) I have not had the issue.

Its definitely a communication issue with the sleep wake function going through the TB to DP cable. I just don't see Apple been able to fix this unless yes they release a special cable.

So if you desire to prevent this problem from ever happening again make sure that your computer never goes to sleep.

Upgrading to 10.11.5 has NOT solved the problem for me either.   I haven't seen the garbled screen upon wake, but I do often get a black screen with the mouse pointer or beachball and the system is hung.   (Running 10.11.4, I would get either this situation or the garbled screen)

Does anyone here know how to read OS X crash logs?

I've noticed odd behaviour with my iMac5k and a DisplayPort HP 27" monitor (about 2K resolution).  HP screen doesn't always wake up, or the iMac display is off and only the HP screen is functional... or worse the iMac will refuse to wake at all. Reboot always fixes.  Going to check the Display port version on the cable. I suspect it is not very new. I am thinking of just turning off the HP display when not needed.

I do wonder if this is an issue on the Mac side - either hardware or OS. The same monitor and cable seemed to work fine on an older PC under Windows 7 for quite some time. I haven't noticed any issues on the iMac5k with Windows 10 and Bootcamp, but I rarely use the Windows install enough to allow it to sleep/wake very often.

I'm so glad I've stumbled on this thread... I've been pulling my eyes out trying to find out why this has been happening. Pretty much I've had some if not all the issues described in this thread.

• slow wakes
• wake crashes (where I have to hard reset)
• scrambled display (when I first plug in)

I've tried disabling sleep, auto poweroff... a bunch of terminal commands to keep my Macbook Pro from going into hibernation. I've turned settings off. I've turned settings on.

I'm on El Capitan (10.11.6)

MacBook Pro (Retina, 15-inch, Mid 2015) w/AMD Radeon R9 M370X 2048 MB

I have an external display hooked up to an Asus MG28U 4k display Thunderbolt (mini DP) to DisplayPort 1.2

I have not found a single "fix" that works successfully.

I'll be following this thread.

I have pretty much being able to reproduce this issue at will

1- shutdown macbook pro 2015

2- startup with lid open and without power

3- after startup complete, close lid

4- reopen to wake

5- close again

6- connect power,usb,monitor(either hdmi or DP)

7- wake via usb or bluetooth

8- video crash

tested with or without automatic graphics switching, resetted PRAM and SMC, latest 10.11.6 El Capitan on a MacBook Pro 2015 with M370X and a Dell U2410

no apps open during testing

if lid is open, no crashes happen. even sleeping and awaking with or without external monitor already connected

also, If I connect the monitor with the lid open and already connected to USB and power, and then close the lid, I can wake it without crashing

so it seems that it only crashes if it went to sleep without a monitor attached in the first place

Just found this thread and I have a similar problem, or I have for some time, but as of today I have NO External Monitors either HDMI or DisplayPort!

I was running OK over the weekend, and then worked with only the laptop for a few hours last night and this morning. When I came back to my desk, I made sure the computer was awake, and plugged in both HDMI (Seiki) monitor and DisplayPort (ViewSonic DVI, via a Thunderbolt to HDMI adapter, and HDMI to DVI cable)... and both appeared properly.

As I normally do, just to be sure, I restarted the computer a NO external monitors appeared! I can get them to show up in Bootcamp (Window 10), but when I do, everything is very slow (external keyboard is very slow to respond, WinOS slow to respond, etc.). Back on the Mac side, still no external monitors, though Keyboard and OS seem to be OK.

Any ideas??