Q: Monitor not waking up after 10.9.3 update

This seems to be fixed in 10.9.4 beta.  So far no issues, albeit only a couple of days of testing.

I will report if it happens again. 

I've noticed that if FCP 10, Aperture, or Mac DVD Ripper pro is open when the rMBP goes to sleep, these apps have to be quit before the external monitor is detected.  Seems its worse when the apps have a window on the external monitor.

You may want to check this awkward behavior with 10.9.4 beta if you can.

This is not fixed in 10.9.4 beta.  It just happened again.  I used to force-power cycle when it happened by pressing power button, but there is a better (or safer) way. 

Command-Control-Media Eject : Quit all applications and then restart the computer

Command-Option-Control-Media Eject : Quit all applications and then shutdown the computer

I don't think my rMBP has a media eject key.  I think Command E is the same as the keyboard eject key

It is definitely better than 10.9.3, but it will happen again eventually.

I'm having the same problem but did find a work-around. I stream some audio (like a radio station) -- when my Powerbook and thunderbolt display go to sleep, both wake up normally as long as audio is streaming (I actually mute the audio so as not to be distracted). It's a drag to be forced to do this, but it allows me to work until Apple REALLY fixes it...

What I do is, set the monitor to never sleep and turn off the TV (in my case) manually. 

Should I turn on monitors first and then wake up the Mac Pro? Or it is the other way around?

When the Mac wakes, it will send out the EDID query.

The monitors must be ready to respond to that query, or they will stay dark.

Yeah that is what suppose to happen, along with a discovery sequence. Do you happen to have the traces to prove that for 10.9.3? 10.9.3 seems to have broke something and its not working the way it should....  seems slow to respond and time out happens.  Seems to not send and EDID when FCP or Aperture had a window open on the external monitor when the Mac went to sleep.

Still happening after the official 10.9.4.  I am losing hope. 

Me too. Really disappointing...

Looked at the post, noticed that there hasn't been anything like this mentioned;

Try;

Intel-based Macs: Resetting the System Management Controller (SMC)

and if required: About NVRAM and PRAM

Ensure the external display is not connected during these steps.

Cheers

Thanks for the suggestion, but resetting PRAM/SMC does nothing for this bug.  This is clearly a bug that is started in 10.9.3.