late 2014 5k iMac boot issues

Discussion in 'iMac' started by josh bear, Apr 3, 2016.

  1. josh bear macrumors regular

    Joined:
    Jan 11, 2010
    #1
    Hi

    I would appreciate any help and advice. I have a late 2014 5K iMac running El Capitan. two days ago after shut down I noticed that the iMac rebooted itself. This is did 4 times and in the end I had to unplug from the wall. Next morning all was fine.

    Since then I have had two failed boot ups with a text message saying the system needed to restart and then this morning after the grey apple logo appeared and the grey bar was two thirds of the way across the screen small text appeared in the top left corner of the screen. Can't recall the text but "Panic" was in there. From here we went into multiple start ups that ended with a circle with a line through it. I then unplugged from the wall, refitted the RAM and booted up again.

    After multiple failed attempts to boot into safe mode I finally got there and I am in the process of saving all critical data onto a hard disk. (I do have TM set up as well).

    What would you advise at this point? is it first aid from disk utility or complete reinstall? or something else.

    thanks for any help.

    Josh
     
  2. varian55zx macrumors 6502a

    varian55zx

    Joined:
    May 10, 2012
    Location:
    San Francisco
    #2
    That truly sounds terrible.

    Wish I could help you.

    Good luck.
     
  3. stuartak macrumors member

    stuartak

    Joined:
    Feb 21, 2016
    #3
    It sounds like you have possibly some corruption of the boot files, If you have a backup of your machine I would just do another full reinstall . If this does not clear and you have some form of warranty I would take it the Apple store. If you do not have any warranty valid before you seek Apple support ~I would prepare a bootable version of El Capitan on a USB and go into recovery mode and boot your machine from your your USB and see if it is more stable . Also if you have access to any Apple diagnostics ( they are available if you search the net) run these which will help you isolate the issue if its hardware related. It is possible you have a disk issue but try the above first.
     
  4. Macbookclinicleadtech macrumors newbie

    Macbookclinicleadtech

    Joined:
    Apr 3, 2016
    #4

    Ok your on the right track , reseating the ram was a logical first step , and now it boots occasionally so you have a hard drive issue as well , I've seen the boot reloop happen over and over as well .

    My guess is you got a bad update and are missing some part of OS X , maddening but fixable . Once you have saved off your data ( you also have a time machine backup ), that good news .

    Boot the mac holding command plus r on your keyboard to see if you can get into recovery mode , if you can use disk utility and run verify disk see if it finds errors , if it does use repair disk to try and fix them , if you can't hard drive will need replacing.

    If it doesn't then go ahead and wipe the hard drive then close disk utility and either do a clean install of El Capitan of reload from your time capsule.
     
  5. josh bear thread starter macrumors regular

    Joined:
    Jan 11, 2010
    #5
    thanks all. I assume there is a diff between safe mode and recovery mode? having real problems activating recovery mode. It's just cmd R straight after power on and hold until it starts, correct?
    thanks
     
  6. Macbookclinicleadtech macrumors newbie

    Macbookclinicleadtech

    Joined:
    Apr 3, 2016
    #6
    Holding command plus r on your mac until you see the apple pop up and then you can let go
    --- Post Merged, Apr 3, 2016 ---
    If the onboard recovery doesn't load you can try internet recovery which is command , option and r held down at startup until you see a little globe appear
     
  7. josh bear thread starter macrumors regular

    Joined:
    Jan 11, 2010
    #7

    Thanks


    Will try the Internet recovery as command r not having any effect whatsoever
    --- Post Merged, Apr 3, 2016 ---

    OK so I did the internet recovery, the globe appeared and counted down 5 mins, then the grey bar appeared and the "Panic text" appeared again followed by the message saying there had been an error and the iMac would restart, which it then tired to do on a loop with the grey bar getting two thirds across really fast then slowing down to a stop and that is where I am now. :(
     
  8. josh bear thread starter macrumors regular

    Joined:
    Jan 11, 2010
    #8
    managed to take a photo of the text that appears as boot up fails. Anyone help with this? IMG_7997.jpg
    --- Post Merged, Apr 3, 2016 ---
    update. checked the disk using single user mode but it says there are errors and the drive can't bar verified. upon startup the bong sounds and the grey bar goes two thirds and then the boot starts again. this happens until the iMac is physically switched off. Can't even get back into safe mode at this point. Looks like a genius appt for me then

    thanks for the help.

    josh
     
  9. josh bear, Apr 3, 2016
    Last edited: Apr 3, 2016

    josh bear thread starter macrumors regular

    Joined:
    Jan 11, 2010
    #9
    update - having tried every other solution on the internet I decided to remove the RAM modules I had bought from crucial at the same time as the iMac and refitted the original ram. I started and tried command R and now I have access to recovery mode! I ran first aid and it said it had failed so I assume now I am going to try a TM recovery
    --- Post Merged, Apr 3, 2016 ---
    new update. Ran disk utility and tried to restore from TM but it wouldn't show the Mac HD to install the backup onto. So went for the nuclear option of erasing the Mac HD and it says erase failed. Any thoughts? The Mac HD is not showing as mounted. it says Not mounted

    Also in disk utility I can see an apple disk image and OS X base system
     
  10. Fishrrman macrumors G3

    Joined:
    Feb 20, 2009
    #10
    OP wrote:
    "having tried every other solution on the internet I decided to remove the RAM modules I had bought from crucial at the same time as the iMac and refitted the original ram. I started and tried command R and now I have access to recovery mode!"

    Obvious problem:
    Bad or incompatible RAM.

    Put your ORIGINAL RAM back in.
    Don't use the bad RAM any more.

    Get -NEW- RAM and try that.

    Send the "known, bad" RAM back for a refund, or put it in a drawer someplace.

    Of course, you now how to work at rebuilding the internal drive.
     
  11. josh bear thread starter macrumors regular

    Joined:
    Jan 11, 2010
    #11

    Hi
    but that "Bad RAM" has been in place since day one of ownership of the iMac with no issues. Not sure it is to blame especially since disk utility was showing errors on the mac hd.

    anyway new update. I rebooted after a power up and went back into recovery mode this time the mac HD showed up in disk utility and repair said it completed successfully. SO I erased it and I am now restoring from a TM back up.

    My plan is to remove all valuable files from the machine and run it for a few days to see what happens. I do have a genius appt booked for Friday.

    thanks for the help all
     
  12. josh bear thread starter macrumors regular

    Joined:
    Jan 11, 2010
    #12
    Hi

    Just closing this off in case anyone has the same issue and find this thread after a search. In the end I replaced the RAM and then repaired the disk as there were errors. Finally I wiped the HD and restored from time machine. 15 days later all working well.

    thanks to all the people who helped.

    Josh
     

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