Yosemite 10.10.3 Second screen big problem

The warranty entitles you to complimentary phone support for the first 90 days of ownership.

Same here....

my issues is with a 2014 15 inch retina macbook pro, my 4k monitor will not wake up after going to sleep. I have to reconnect ( physically ) the screen.

I have a similar, yet worse problem. My 27" 5K iMac is not longer sending a signal to my 30" Dell via mini-display port to display port . Hope apple gets a fix for this soon.

I have the same issue, with an Asus PQ321Q. It started with a lot of flickering and the display going on and off. Now every time the mac display sleeps the external monitor disconnects. has to be unplugged and reinserted each time.

C'est quoi le deuxième écran?

Experiencing the same issue on 2012 Retina Macbook Pro, OS X 10.3.3 with an external HP x23LED display (1920x1080) connected with a mini-display port to DVI adapter.

The external display receives no signal after some time, though the display is shown in System Preferences and apps appear to be running on it when connected. Might be that this occurs when going to or waking from sleep (I've yet to see it switch off while in use). Only started happening since installing 10.3.3.

Restarting the Mac and/or display has no effect. Same with disconnecting and reconnecting the display, though it appears/disappears correctly in System Preferences.

I've got the EXACT SAME setup, macbook pro retina 2014 ( the high end model) with a asus pq321q screen. I've contacted apple, they said they would informe me this week.

french speaking sorry for my english..

I found this:

Using 4K displays and Ultra HD TVs with your Mac - Apple Support

Looks like 10.10.3 brought an update where mid 2014 macbook pros can use these displays in SST mode, and I am betting this has done something to break support for running them in MST mode. Sadly, I have a lat 2013 macbook pro, so I'm stuck with MST. Might try it and see what happens... or might need to buy a new macbook, which is not great since no doubt there will be an update in a few months.

My issue is different , all works well, like it used to, but as soon as I go to sleep ... the monitor will not get back.

*I go to sleep = ( I mean the computer ... )

I think that we have two separate problems here.

1. Failure to wake up from sleep

On my iMac, I've encountered the same problem with a separate 27in LG high res monitor. The only cure that I've come up with is to change the energy saver settings in the Preferences to 45 minutes. Not exactly environmentally friendly, but something has happened here with the system software, since this was not a problem in prior OS releases.

2. No signal or corrupted signal to the external monitor

The existing iMac was a replacement for an older 2009 Intel Core 2 Duo iMac, which mysteriously lost the ability to display anything on the external monitor after a system upgrade. I discovered that Apple apparently dropped support for the video card after 10.7. After serious time troubleshooting this, including trying the external monitor with a similar vintage 24in iMac where it did work, there was no other conclusion to come to. I'd suggest anyone encountering problems with external monitors with iMacs or any Mac laptop to try the monitor with another machine or with something of newer construction. That may provide your answer. It will not fix the problem, but will let you find out if your video card was one of many that Apple chose to drop support for.

With the other issues that many posting here have indicated, I don't think that Apple's quality control or their support for their product is what it used to be five or six years ago.

FWIW,

L Cranston