27" iMac in constant kernel panic/boot screen

[Bedunton]

Hey guys,

My mid 2011 27" iMac is acting up. I've never had an issue until yesterday when out of the use it randomly shut off. I turned it back on, got the "your computer shut off because of an issue" and continued as if nothing happened. 5 minutes later it did it again. Same message when rebooting. Finally it went into kernel panic mode and continuously began to restart and shut off. I was able to run a diagnostics on it and got this message " 4MEM/9/40000000:OX88933898
I found out this was a RAM issue. I upgraded my 4G of RAM by adding 8 more a year ago. I thought perhaps something gave out so did some trial and error and could not figure it out. Now my computer will not get past the white screen with the apple logo and a loading bar. The computer shuts off half way through the loading bar. I also will occasionally get this message I posted below (right before it shuts off). Any advice what this could be? Running in safe mode/running diagnostics will not work anymore.

 

[Bomb Bloke]

The progress bar you see under the Apple logo indicates that the system is attempting to repair potential file system damage, using fsck. The fact that this process is looping indicates that it's finding corruption and failing to repair it. This file system corruption would be a side effect of the RAM-related shutdowns.

And this point, I would be considering a full Time Machine restore. If you haven't been backing up your system, it may still be possible to extract the data, but odds are you'll need to format the drive before you can use it again.

The odd thing is that the system is kernel panicking while running fsck. That's very much out of the ordinary, and suggests that you haven't solved your RAM troubles just yet.

You haven't been clear on what you did as part of your "trial and error". If it hasn't already been done, I suggest putting the stock RAM back into the unit for now and leaving the aftermarket parts out.

 

[Bedunton]

Thank you for the reply. I really appreciate it.

Yes, it's been quite odd and thankfully I backed up all important items as soon as I noticed an issue a couple days ago.

I'm sorry I didn't specify the "trial and error". I removed a RAM card and tried rebooting the computer to see if I could find the bad puzzle piece. I did this many times and in as many combinations as I could think of, trying to see if it was a chip or a slot problem. No matter what I tried it still malfunctioned. I currently do have the original cards in their original slots.

 

[Bomb Bloke]

Let's see if we can get some more clarity on what's going on with the disk repair process, by initiating a check manually so we can see the results (which also prevents the automatic reboots when the tests are done, so we can determine whether the computer is performing those on purpose or not).

http://support.apple.com/en-us/HT203176

Use either the Disk Utility or fsck method, whichever you find easier. If this at least stops the reboots, then things're looking hopeful.