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Late 2009 i7 27" iMac Crashed after Yosemite

I purchased a late 2009 27" iMac from a friend of mine earlier this year. It ran beautifully...until I installed Yosemite. It started off just fine, then slowly began to become glitchy and occasionally freeze. Then came the serious freezing. It would freeze and then would not boot up into OS X. It gets the start up chime, then either gets stuck in a reboot loop or stays frozen on a white/grey screen indefinitely. Safe boot works...sometimes. I've talked to Apple support multiple times and I am now in contact with a senior advisor, however, nothing seems to work. I reset SMC, PRAM, reinstalled OS X, reverted to Mavericks, restored from Time Machine...everything. If I erase the hard drive and completely reinstall everything from scratch, it will SOMETIMES work...for about a day, or until I try to restart and then the problem starts all over again.

I took it to the Apple store and they thought it was my hard drive...it isn't because I replaced it. One of the associates claimed that he inserted Apple RAM and it worked just fine, then put my Crucial RAM back in and it still worked. I got it home and it worked for about a day until I decided to restart and then nothing again.

I replaced my hard drive, ran diagnostics on the RAM (Crucial) and have tried every test I can think of. I used MemTest for the RAM and I even downloaded NovaBench from the App Store to see if it could find anything. It ran and seemed to pass every test EXCEPT the GPU test. The app claims that my video card (Radeon HD 4850 512mb) may not be compatible, although their website shows data for that exact video card. I can't seem to find any other app that will run GPU diagnostics. Even the network diagnostics that the Apple store runs passed every test. Holding "D" at startup does not run the Apple hardware test. I have a bluetooth keyboard, could that be why?

I'm thinking it could be hardware, but I have no data to support that assumption. Could it be firmware? I would love to hear if anyone else is having this problem because I've been dealing with it for about a month with no light at the end of the tunnel. I am incredibly disappointed and I sincerely hope it's simply a coincidence that upon installing Yosemite my computer craps out.

Posted on Dec 3, 2014 12:58 PM

19 replies

Mar 14, 2015 9:54 AM in response to Baby-Boomer-USofA

Hey Baby Boomer, all the diagnostic testing the world would not reveal a "video card" problem. They had to run it and see when it crashed. I left the machine with the apple store for 3 months while this baby boomer winters in sunny arizona. Well they called, oh no crashes. I said keeping running it. 3 days later callback, OMG it crashed. you were right. Yea! So I'm over 50 and i know what I'm talking about. Heck! I was buying iMacs before you were born..... That being said. They have to mid April to continue running it to ensure nothing else is wrong. I love my iMac...I love my Apple products and this is only time I've had to continually go back over and over again to get this fix. I can't wait to get home in mid April and give my iMac and good run ....cause if it happens again, I will be hopping "****** off".

Thanks for replying to my issue.

Mar 14, 2015 1:13 PM in response to Cynthia Mcdonagh

for being persistent!

So I'm over 50 and i know what I'm talking about. Heck! I was buying iMacs before you were born.....

😁

Mar 21, 2015 8:25 PM in response to Baby-Boomer-USofA

What kind of video cards to people get to replace the old one?

I have a late 2009, 27", with the ATI Radeon 4670. It's been freezing about once a day for a while now, and I feel like it coincided with the Yosemite upgrade. The mouse still works after the crash, but that's it. I'm not very experienced with checking crash logs, but I can't seen to find any kind of kernel panic. Based on what I've read so far, it looks like it could be the same compatibility issue between Yosemite and the video card that I am reading about here.

As much as I'd like a new video card, that seems like an expensive hardware repair for a software problem. It seems like an alternative would be to roll back to Mavericks (or earlier?) or wait around with fingers crossed for a driver update. Just trying to explore my options.

West1232

Level 1

4 points

Jun 26, 2016 3:58 PM in response to sickfrusciante

Late to the forum guys, but I would like to confirm it indeed is the GPU (Graphics Card) that crashes after you update to Yosemite OR El Capitan. For some reason the OS makes the GPU run at 100% randomly even when the computer is not being used causing it to crash and fail. At boot up, it will go to a white screen after the Apple logo. It will only work in safe mode (Hold "Shift" at bootup till Apple chime) unfortunately you will not get the full apple experience. Apple will not fix this issue so you will either have to replace it or take it to a 3rd party store that can get the video card with the Mac OS drivers. This is a software issue glitch and this has been happening to many people after the software update. I recommend you stay on Mountain Lion for now.

Late 2009 i7 27" iMac Crashed after Yosemite