Q: Monitor not waking up after 10.9.3 update

I installed yosemite preview... all working again.

...with only one slight hick-up.

So I guess, ressources to fix the problem on mavericks are quite tight up right now, with all the releases just now.

I think Yosemit will appear soon.

greez

- raf

My monitor issues all but disappeared after the 10.4 update but have since returned to about the original infuriating state that I had before.  Overnight sleeps are recovered from with no issues usually but if my mPro has only slept for a few hours then my HP 2159 monitor does not wake up.My Apple monitor always recovers.  The only solution for me is a restart. I also use Parrallels Desktop.  I now also have to shut down Parrallels dektop or my macPro won't allow a restart.  That was not the case before.

I don't know why the issue deteriorated again but I am right back to where I started.  I have to do a restart most times after a short sleep.

I've had all these issues with 2x NEC EA244UHD monitors on a new MacPro since 10.9.4 (thunderbolt connected), the monitors not waking from sleep. As a temporary workaround I simply cycle the mains power to the monitors when I know the video signal was present. Though inconvenient it does the trick, and it is a problem that should have been fixed by now, especially as these issues apparently mostly affect the high end computers. But to those who have asked, updating to the release version of Yosemite did not help my wakeup problem at all, though it did at least finally cure the problem with the old D500 display drivers.

Hey Folks,

I am new to posting here but I have a similar problem. I have a MBP Retina 15" Late 2013. I have an external monitor HP w2207 connected via DVI and the apple to Thunderbolt DVI Adapter. The same monitor connects to an HP machine running Win8.1.

Last known working state was prior to upgrading to Yosemite. I did not ever install the beta. Everything worked fine and my screen woke up from boot. After Yosemite, the monitor does not wake up from boot and says no input signal. If I unplug the connector and plug it back in, it works fine but obviously annoying.

I tried Discover Displays and that did not help. Interestingly enough, I tried something running out of options to turn on Airplay mode to my apple TV and magically that wakes up my monitor. I then turn it off and my monitor stays on. That is an improvement in not having to unplug the connector but hardly a fix.

I would love to get this resolved! any feedback is appreciated!

Interestingly, my previous monitor issues with respect to waking up after a sleep disappeared after I updated to Yosemite (using a Mac Pro)

BUT

I now have an issue if I do a restart.  Whenever I restart the arrangement of my displays reverses.  This was weird when it first occurred  because it was not immediately obvious that the mouse had to be moved in the opposite direction to get to the other monitor.  When the arrangement is again changed in settings it maintains that configuration until the machine has to restart again (sleeping does not present the issue).  A PRAM reset does not sort the issue out either. 

Each system upgrade presents me with new challenges.  My latest variation is the easiest for me to deal with so far. I just mention this in case you go down the same road later.

Same problem here with my Thunderbolt Mac display.  After updating Yosemite (10.9.5), the issue resolved for about a week, then returned inexplicably.  Very frustrating to have to unplug the thunderbolt plug and reinsert to get the monitor to wake up.  Apple- please fix this!

I too have this problem. Just started today. but just got this 2013 MacPro a few weeks ago.

Put into sleep mode this am and return 6 hours later. Wake system, No video. Monitor still in sleep mode. (Light blinking) This is a 1 monitor setup with the main monitor being a LG 27" Ran thru the HDMI Port. OS 10.9.5

Anyone find a fix for it yet ? Just did a reset of pram not even a week ago.

Apple ?

Correct resolution and timing to your display depends on the Display answering an EDID query from the Mac. These queries are sent at Startup, when the Mac wakes from sleep, and when a cable is inserted.

If you have at least one display working, you can also use:

System Preferences > Displays ...

Hold down Option in this pane and the ( Detect Displays ) button should appear, which sends the EDID query to all connectors.

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If the display has activated its own internal sleep, as well as Mac sleep, it may not respond to the EDID query when the Mac sends it. That could cause it to remain dark.

Try sleep-and-wake your Mac again to see if it will respond better, or unplug and re-plug the cable at the Mac end.

At this time I have only 1 monitor in use.

With same monitor I never had this happen with my 2012 Mac Mini. Sleep mode in monitor is turned off. This leads me back to the 2013 Mac Pro.

Monitor is wired via HDMI Tried the disconnect of HDMI Cable but did not wake up the monitor. Hate to keep turning it off and back on as any unsaved data will be lost. (That's why I'm in sleep mode. To finish what I was working on at a later date.) Being I never had this problem with the mini looks like a Mac Pro problem. Mac Mini was also connected via HDMI

I have the same problem but it only just started a few days ago. I have an old Westinghouse 19" DVI connected via the DVI to Displayport adapter. This 2012 Mac Mini has run Lion, Mountain Lion, and Yosemite with no monitor sleep issues until this past Monday morning. Cycling the monitor power button brings it back but why is it happening?

Had a similar problem with a 13" MacBook Pro mid 2012 (bought new 01.2015), Yosemite 10.10.2 and a Philips 27" external monitor.

It worked perfect;y fine in the beginning using a direct Mini DisplayPort to HDMI cable to connect to the HDMI monitor. After a while the monitor wouldn't wake up anymore after waking up the MBP.

Tried everything such as repairing permissions, resetting PRAM, unplugging/re-plugging the HDMI cable with sporadic success.

Finally I bought a new cable and everything just works fine :-) Actually I changed also the configuration to: Mini DisplayPort to HDMI adaptor plus HDMI to HDMI cable . However, I don't know whether the change of cable configuration or the simple replacement of hardware (cable) did do the trick.

I had a similar problem, for me the monitor was the cause. It was cycling through it's inputs to find a live one (HDMI, DVI, HD15) and I guess it took so long to come back to HDMI my mac thought the monitor wasn't connected.

Setting the monitor to default to HDMI and not search the other connections solved it.

27 inch late 2013 iMac, Hp Compaq LA2405wg second monitor connected by DVI with DVI-mini Display port connecter, using Yosemite. This solved the problem. My monitor was cycling through inputs, too, and I stopped it from cycling and set it to go to DVI first, and now it works fine. I have the same monitor on an older imac as second monitor, too, and it solved the problem (that computer is using Mavericks). So, not really a Mac problem, it turns out.