The fault is the Display port to DVI adaptor. I brought the one home that I use at work and it's fine. Put back the one I've been using at home and no display, so that must be the issue.
It is, however, an amazing coincidence that it failed on the exact same day that I upgraded to Mountain Lion. I can't say that the software upgrade caused the hardware failure, but it's an amazing coincidence...
Actually, my problems started before I upgraded. I really believe it is Messages/Messages Beta causing the trouble. I get imagent going crazy now whether my monitor is connected or not, or whether I have launched Messages or not. It was only when I uninstalled Messages Beta that it got *slightly* better.
This is a pretty significant bug.
You're right - this is definitely not a coincidence or case closed. Unfortunately, bodinp has marked this as solved so no one who actually knows what they're doing is going to try to solve this anymore. I'm going to start a new thread and I'll post a link to it here. Anyone who is having the problem please post to the new thread so it will get noticed.
Second, I've had this problem once before when I upgraded to Lion. In that case, I was using a hi res monitor connected by VGA. When I started having the problem I tried connecting by Dvi, and that solved it. So if you're external stopped working with mountain lion, you are currently connecting by VGA, and your monitor has a dvi plug you might try changing how you're connecting to your monitor. If, on the other hand, you are like me and your monitor only has a VGA plug, or you're having the problem even with a dvi connection, please post to the new thread.
It ***** that this has been marked close, I've added this message to your new thread, but here it is incase anyone is checking in on this.
I had posted this as a question on my own, but no one has followed up to it. Anyway, this is the issue that I'm experiencing with my external display
Everything was working fine the day after updating to 10.8 when I hooked up my NEC monitor to my MBP (mid 2010) with a DVI-mini display port adapter. However, when I hooked it up to the closed MBP the next day, it refused to wake when tapping the bluetooth keyboard or trackpad. When I opened the MBP, the screens came on, but looked inverted. What was red, was blue... the blue folders where golden, etc. But it wasn't a true inverted, like when you check the box in the accessibility panel. Because I looked there, nothing was checked. When I clicked the box, it went to a "true" inverted appearance.
I unhooked the monitor, the MBP screen appeared normal. Plugged the NEC back in and it appeared inverted again. When I mirrored the monitor, however, everything was fine.
A quick fix thus far has been the VGA adapter, everything is fine there. I can have both the MBP and the NEC running as per normal.
A call into Apple under my apple care proved to be fruitless... the suggestion was to zap the pram and smc, both not rectifying the situation.
The apple tech walked me through a remote restore restart. There, the monitor hooked up to the DVI-mini display port was working absolutely fine! I opened the lid while in the restore partition, and bingo! it was working fine. SO hardware can not be the problem, nor can the adapter be faulty.
But I was still told it might be a hardware issue and to bring it in under apple care. I was told if they can't replicate the situation in-store, that they'd be able to escalate the issue to the engineers.
Before I updated, I cloned my system with superduper!, a bootable backup of 10.7.4. I figured I'd check to see if the issue was present in Lion. It isn't. I believe this to be a bug in Mountain Lion. However, the solution from Apple is to still bring in the MBP to have a genius take a look around. Frankly, my three phone calls over the issue to apple should be enough to make some notes and send the issue off.
I'm usually a dual screen worker, so I'm not at a loss. But this seems to be a bug that isn't being acknowledged.
I was about to attach a screen capture to show what I'm talking about, but uh, the screen capture came up normal on the main (external display) and inverted on the secondary (MBP) display. So, it must be software related. perhaps a third party program and 10.8 not playing nice together. But why only affect the DVI connection?
Anyway, I decided to see if the issue was present when I changed which monitor is the main display. It's still wonky. I changed the rotation to 90 degrees and everything is back to Normal! Aside from the fact that I'm looking a 24" screen in the vertical position.
I really don't want to do a fresh install... but I may have to.
That's what is going on with me… so yea, not case closed.
OK, this is the straw that breaks this camel's back:
I have been extremely dissatisfied with Lion and now Mountain Lion.
I use an Apple 2560x1600 (yes, not 2560x1449) cinema display as my main screen. The laptop sits behind it on a shelf, with its lid closed and its screen off. This worked superbly well up to Snow Leopard.
It stopped working in Lion, but I did find the workaround sudo nvram boot-args="iog=0x0"
However in 10.8.2 this does not work. Setting the kernel in 64bit mode does not work either.
If I leave the laptop's screen on (i.e. lid open) then I tend to lose the mouse pointer on the other screen, there is light I do not want, and so on.
Mountain Lion is uncomfortable for content creators, and a simple nuisance compared to Snow Leopard.
In September 2011 (not 2012!) I bought a second laptop just for the purpose of testing Lion while still being productive on my Snow Leopard laptop. In over a year of struggling I have not succeeded in switching yet.
I am so fed up that I will now just switch to Ubuntu Linux.