Eoin Sharkey1

Q: 20-inch imac sticks on boot screen

This is an older  20 inch iMac with Yosemite OS.

 

After a short power-cut last night, the iMac no longer boots up.

 

Symptoms :

 

Power-on as normal, chime, then grey boot screen with dark grey Apple logo. Progress bar fills to 30 -40% reasonably quickly then stalls.

 

After about 10 minutes the iMac powers down.

 

Already tried :

 

- Reset SMC

 

- Reset PRAM

 

- Removed the Logitech Universal Receiver

 

Same symptoms each time.

 

Given the age of the device, I am suspecting PRAM battery - anyone got any similar experiences  ?

iMac (20-inch Mid 2007), OS X Yosemite (10.10.2)

Posted on Sep 24, 2015 12:20 AM

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Q: 20-inch imac sticks on boot screen

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  • by D.Cohen,Helpful

    D.Cohen D.Cohen Sep 25, 2015 11:00 AM in response to Eoin Sharkey1
    Level 6 (8,424 points)
    Desktops
    Sep 25, 2015 11:00 AM in response to Eoin Sharkey1

    Hi! I've once had the same issue. Unfortunately, I had to reinstall OS X it get it fixed. Try the steps below and if these steps don't work, use OS X Recovery and reinstall the OS.


    Safe Boot:


    - Shut down your Mac

    - Wait until your computer turns off and after that press the Power button

    - Right after you hear the startup tone, press and hold the Shift key

    - Release the Shift key when you see a grey Apple sign and the progress bar below this sign

    - After your Mac boots up, restart it as you usually do.


    If this doesn't help, follow the instructions below:


    - Shut down your Mac

    - Wait until your computer turns off and after that press the Power button

    - Right after you hear the startup tone, press and hold the Shift key

    - Release the Shift key when you see a grey Apple sign and the progress bar below this sign

    - Once you see Desktop, start a Disk Utility scan to detect and repair file system errors (don't forget to choose your main hard drive)

    - Click on Verify Disk and then, if asked to fix problems, on Repair Disk

    - After this, click on Verify Disk Permissions and then on Repair Disk Permissions

    - After the process is finished, shut down your Mac and turn it back on after about 30 seconds


    Take a look at the steps suggested by Apple in this article:

    https://support.apple.com/en-us/HT204267


    Reinstall OS X:

    Make sure you are connected to the Internet. After that, follow these steps:

    1. Restart your Mac. Once it restarts and the grey screen appears, press and hold the Command and R keys.
    2. Select Disk Utility and click Continue.
    3. Select your startup disk on the left and click the Erase tab.
    4. Choose Mac OS Extended (Journaled) from the Format menu, enter a name, and then click Erase.
    5. Select Reinstall OS X, click Continue, and then follow the instructions on your screen.


    Hope this helps!

  • by Acm001,Helpful

    Acm001 Acm001 Sep 25, 2015 11:12 AM in response to Eoin Sharkey1
    Level 3 (623 points)
    iPhone
    Sep 25, 2015 11:12 AM in response to Eoin Sharkey1

    If it was on and writing something to disk when it shut off it most likely corrupted some files. A reinstall may be only solution.

  • by Eoin Sharkey1,

    Eoin Sharkey1 Eoin Sharkey1 Sep 25, 2015 11:08 AM in response to D.Cohen
    Level 1 (45 points)
    Sep 25, 2015 11:08 AM in response to D.Cohen

    D.Cohen

     

    many thanks for that. Useful input, given the nature of the event (sudden power cut), corruption of disks with OS must be a candidate ..

     

    Apologies for not replying sooner, I thought I was 'subscribed' to this post (haven't used the Apple forum in a while), so didn't realise you'd replied.

     

    Will try your suggested remedies this weekend and post back.

     

    Cheers


    Eoin

  • by rkaufmann87,

    rkaufmann87 rkaufmann87 Sep 25, 2015 11:24 AM in response to Eoin Sharkey1
    Level 9 (58,956 points)
    Photos for Mac
    Sep 25, 2015 11:24 AM in response to Eoin Sharkey1

    IF the re-install does not work, then the HD may have crashed. If you still have the original install discs that came with it run Apple Hardware Test in extended mode 2-3 times back to back. If errors appear on any pass, then you know you have a hardware problem. You have to run it multiple times because AHT does not always find errors on the first or second pass.

  • by Eoin Sharkey1,

    Eoin Sharkey1 Eoin Sharkey1 Sep 26, 2015 1:38 AM in response to rkaufmann87
    Level 1 (45 points)
    Sep 26, 2015 1:38 AM in response to rkaufmann87

    Thanks RKaufmann87, DCohen & Acm001,

     

    Booting into Recovery mode is a new thing for me and a neat facility. Sadly it seems to show that the hard drive is not just severely corrupted but possibly terminally dysfunctional.

     

    Within Recovery mode I can use DU to verify/repair the disk neither will complete. Nor can I erase the disk, or mount it.

     

    Re-installation is not possible since the disk is not presented as a target.

     

    Booting into single-user mode reveals that /sbin/fsck -fy completes 3 cycles identifying an error but failing to fix it.

     

    I am now turning my attention to rescuing remaining files on the disk.

     

    There is a Time Machine backup to a separate disk-drive, unfortunately, as this is the only Mac in the household, I cannot view/verify the latest backup.

     

    In single-user mode I can still view all the important files; however rescuing them doesn't seem straightforward since I cannot seem to mount (e.g.) a USB memory stick.

     

    Any pointers towards recovery of files in single-user mode appreciated (I guess there may be other posts already , which will research later), as will rebuilding the machine with a new hard-drive.

     

    KRs