Successful resuscitation from iMac hard video freeze! - Please try this at home.
For those of you with intimate details of the iMac's inner workings, perhaps this will provide some insight into the problem with the hard video freeze. I was able to successfully resuscitate my iMac without a hard reboot, by turning on Screen Sharing from my MacBook Pro. The iMac was still fully functional and accessible from the MacBookPro. I then went to the Display preference panel on my iMac and changed the resolution. BOOM! 
Back on. (Sorry to be so excited, but I haven't seen this documented anywhere or else I would have used the solution before). I hope I can do it again!
So fellas/experts, use this info and lets get a real solution to this frackin problem already!!!
If I can do it again after the next video freeze I will let everyone know.
Other things to potentially try....
Does it need to be a resolution change or would detect displays work?
Does the USB input still work on the dead screen computer (I forgot to try the mouse connected to the iMac while it was frozen).
Will running the iMac at a different resolution avoid the problem in the first place (might be helpful for those who can't do the screen sharing solution)?
Back on. (Sorry to be so excited, but I haven't seen this documented anywhere or else I would have used the solution before). I hope I can do it again!So fellas/experts, use this info and lets get a real solution to this frackin problem already!!!
If I can do it again after the next video freeze I will let everyone know.
Other things to potentially try....
Does it need to be a resolution change or would detect displays work?
Does the USB input still work on the dead screen computer (I forgot to try the mouse connected to the iMac while it was frozen).
Will running the iMac at a different resolution avoid the problem in the first place (might be helpful for those who can't do the screen sharing solution)?
Comments
I'm a massive Apple fan and have bought about 15 machines in the last decade, always singing their praises etc but I can't pretend that I'm not enormously disappointed with how long this problem is taking to fix. I have no problem with systems having problems, it's a complex business, but what I care about is how hard the company is trying to fix the problem - and I have no faith at all that Apple are working hard on this at all.
I nearly bought 'returnyourimac.com' the other day, the plan being to setup an online petition (name/serial number) to get them aware that there's hundreds or more users out there deeply annoyed by this problem - then I remembered I haven't got a clue how to make websites!
Does the USB input still work on the dead screen computer (I forgot to try the mouse connected to the iMac while it was frozen).
My iMac has not frozen since I rolled back to the original software (which was prior to the recent updates, which I have not had the stones to apply), but before I did that I had an odd incident that I wish I had tried to replicate. I use the wired keyboard but the wireless Mighty Mouse. I had a freeze (cursor movement but not able to select anything) and suddenly it occurred to me to try plugging in the wired mouse. Boom: instantly responsive desktop. Now, it's not that the computer lost its connection to the wireless mouse, because the cursor still moved. It's like the computer "forgot" how to interpret a click. But plugging in the USB mouse, causing the computer to have to recognize the new input, must have triggered something, just like changing the resolution.
This only worked once...I've had freezes since and had to hard restart them all.