WaxMechaniK

Q: iMac stuck in El Capitan installation loop, cannot boot...

Hi all,

 

We have just purchased a refurbished iMac on auction to replace a much older one which had stopped working. It's a Mid 2010 iMac 21.5inch, i3, 500GB and upgraded to 16GB RAM. The model number is A1311 / MC508LL/A. However I'm having problems immediately.

 

It switched on fine like a new computer, entered our details etc, got to the desktop screen, began to install software updates, Skype and customise the wallpaper, but within half hour to an hour of it being on, it suddenly rebooted itself, when it came back on I had a kernel panic screen, then it displayed the Apple logo with loading bar, but with a lot of white text on black overlayed on top.

 

I restarted but it refused to boot. It would not boot into safe mode either. I managed to boot to Recovery mode and attempted to reinstall the OS, allowing it to download the latest version of El Capitan (which it had on there anyway), but the installation would either get stuck at about 28 minutes remaining with the grey loading bar screen, or get to about 10 minutes remaining on the blue loading bar screen, and just reboot itself. Most of the time I see the kernel panic screen which disappears by itself and reboots.

 

I then created a bootable El Capitan USB using a working Mac, booted the iMac using this, erased the hard drive and then installed the OS from fresh using the USB installer. However I'm having exactly the same installation loop/reboot issue. I've tried this twice with no luck.

 

Between all this I've tried resetting SMC and PRAM several times. I've also run Disk Utility which doesn't find any errors using First Aid.

 

I'm going to assume there's a hardware issue here but I cannot identify it. Looks like it needs to be returned as faulty, but would appreciate any advice on anything else I can try to get it working please?

 

Thank you!

iMac, Mac OS X (10.6.8)

Posted on Jun 22, 2016 3:06 AM

Close

Q: iMac stuck in El Capitan installation loop, cannot boot...

  • All replies
  • Helpful answers

  • by Mike Sombrio,

    Mike Sombrio Mike Sombrio Jun 22, 2016 3:51 AM in response to WaxMechaniK
    Level 6 (17,233 points)
    Apple Watch
    Jun 22, 2016 3:51 AM in response to WaxMechaniK

    Did you upgrade the ram yourself?  If so remove it and reinstall the original ram and test.

    Can you boot the iMac in Safe Mode? Try safe mode if your Mac doesn't finish starting up - Apple Support

    If you can see if you can post a recent panic log Mac OS X: How to log a kernel panic - Apple Support

    The  seller should have provided the original gray install discs, if so try running the Apple Hardware Test from disc two Using Apple Hardware Test - Apple Support

  • by WaxMechaniK,

    WaxMechaniK WaxMechaniK Jun 22, 2016 5:19 AM in response to WaxMechaniK
    Level 1 (4 points)
    Desktops
    Jun 22, 2016 5:19 AM in response to WaxMechaniK

    Hi again,

     

    The machine came with the 16GB of RAM already installed, safe mode does not boot, and it did not come with the grey discs.

     

    But, I tried something else. I reseated all the RAM modules, at one point it beeped 3 times, another time 1 beep, and like magic it booted to login/desktop! It read the 16GB of RAM fine. So I restarted just to be sure, however I had the same kernel panic errors as before. So I took out the RAM and noticed that 2 of the sticks were Crucial RAM sticks, while the other 2 were Kingston RAM sticks. I left the Crucial RAM in and took one Kingston RAM out... kernel panic. Took both Kingston modules out and it booted fine. Restarted again, booted fine. So it seems that the Kingston RAM is faulty, possibly from another computer and/or incompatible. I tried the Crucial RAM in different banks too so the banks aren't faulty.

     

    It looks like the RAM was upgraded by the person who used the computer before. I have just had a response back from the seller and they told me that the RAM was upgraded a year ago. It looks like this was just the sellers own machine and not a actual refurb. Not sure how much truth there is with this but I'm going to ask for a partial refund as we've paid for a machine with 16GB of RAM and only getting 8GB due to half being faulty...

     

    I guess that solves that problem unless anyone else has any other thoughts?? Thank you all.