Installed Mavericks, now HDMI Monitor is black. Any ideas?

same here, with a brand new 15" mbp retina display, hdmi out is black when plugged but I can see the cursor.

if I reboot in recovery mode it works... how can we know which OS version is running in recovery mode?

At least I made hdmi out work in Bootcamp with win7

isn't that ironic?

ok guys i got it working fine 🙂

the solution was already posted here before, I DOWNGRADE it to 10.9.2 and works perfectly.

in my case, got issues only with the Server App which had to be downgraded also and created me problems with the Open Directory, got me a lot of troubles, but i got it working 🙂

it is a shame that Apple force us to be on a lower version, only because they did an improvement for the 4k monitors (which no one uses) 👿

for the ones interested:

follow the instructions on the site - http://osxdaily.com/2013/10/23/create-os-x-mavericks-install-drive/ -

turn off the internet on your computer and install it from the USB stick

I have a Macbook Pro 2011 and have just upgraded to Mavericks 10.9.4 and now it will not recognise either of 2 LG LED and LCD Televisions.

This has worked flawlessly until this stupid update. I seem not to be the only one suffering, I suppose we will have to wait until Apple get their finger out (again) to solve this...probably the Autumn when Yosemite arrives...pleas not another raft of glitches and problems like we had with Mavericks from day one.

Apple products are supposed to be superior, I now have moved away from iPhone, My iPad is now updated and on the iPad Mini there is no Flash for the camera??? Apple are lagging behind and I have always been a pro Apple buyer, Steve Jobs must be spinning by now?

This works perfectly for me .

I have retina MBP late 2013 model with intel IGP .My AOC monitor used to stay blank on both HDMI and Display port adapter after 10.9.3 update.But HDMI used to work fine with my Samsung TV .

Unchecking this option in mission control made my monitor usable again .

Thanks

Sorry, BUT unchecking what?

keltickev mentioned this on page 3 of this discussion

"Go to apple system prefs, Mission control, and uncheck the "displays have separate spaces" box."

Hope this helps

BUY THIS CABLE: http://www.amazon.com/Cable-Matters-SuperSpeed-2048x1152-1920x1200/dp/B00BPEV1XK

I've had this problem with my external monitor since I installed the 10.9.2 update. Tried PRAM resets, time-machined (fruitlessly) back to 10.9.1, swapped out kext files (computer gave me white screen of death), bought different mini-dvi cables, sent Apple bug reports, made threats, cried myself to sleep, etc. NOTHING WORKED-- short of buying a new imac because I'm a bajillionare with plenty of time and money to throw around.

After about 4+ months of not having an external monitor, pretty much everyone knew of my problem because it was always my wet blanket that I'd throw into a conversation when work came up. Had a friend recommend me this cable because it turns an available USB 3.0 port into an HDMI/DVI output. High resolution, video on it lags a little, colors might be a little wonky so basically: 1. Don't play video on it and expect a good time, 2. Don't print preview stuff on it.

I haven't tried the Yosemite update yet and have only heard wishful rumors that external monitors work now. For $50 however, this adapter is a cheap and usable fix to end the frustration of having a huge blank screen burning into the side of your face every time you're working on your computer.

Hope this info helps. Let me know if you have the same success!

Mac Mini 2011 (i7, 16 GB RAM, Radeon 6630M)

Two Samsung monitors: 1080p (HDMI->HDMI) and 1440p (Thunderbolt->DisplayPort)

Worked flawlessly a long time, but since two month occasionally the 1440p monitor goes black. After 5-30 seconds it works again. Tested the monitor with other (non-apple) hardware and it works all the time.

Seems it have something to do with OSX updates? This is really annoying.

I wanted to buy a new Mac in december, an 5k iMac, but if apple allows such flaws in their system I am not convinced to spend so much money for a new product. I will wait a few weeks more if apple manage to fix their display driver, otherwise I will buy an other system. For me the most benefit of the apple computers had been the OS, that not annoys you all the time, but with the latest OSX design changes and now such bugs I don't really see a point in paying high prices for apple hardware.