dual monitor freeze on sleep

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dual monitor freeze on sleep

Mac OS X 10.9.5. Current model iMac: 3.5GHh i7. 32GB main mem. NVDIA GeForce GTX 780M 4096MB.

Runs fine without a second monitor. Sleep, both manual and timeout, works fine. Press any key awakes.

Plug in a second monitor (2 month old 27" Thunderbolt display) all works fine until Sleep happens, both manual and timeout, and then system is hard frozen. No wakey. Press and hold on/off key for a long time. Wait. Press on/off key 3 times, reboots and all is as before.

Only solution: Never sleep. Turn off at night to save screen hours.

iMac (27-inch, Late 2013), OS X Mavericks (10.9.5), Thunderbolt display is 2nd monitor

Posted on Sep 28, 2014 5:24 PM

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Answer 1

Jan 8, 2015 11:49 AM in response to ptsw

Hi! Did you ever find a solution? I just bought a 2013 iMac and have the same problem- except mine will allow a login after sleep after an initial freeze of 4-5 seconds. Dual monitors as well.

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Answer 2

Sep 29, 2015 6:45 AM in response to ptsw

I was having a similar problem and the solution posted at the bottom of the thread here worked for me. It was related to the system switching automatically changing graphics mode.

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