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User profile for user: Jacobo
Jacobo Author
User level: Level 2
228 points

Mac Pro Shuts Down During Startup.

Hi there,

Here are the sequence of events that eventually led to my Mac Pro's inability to boot😟.

1. Upon pressing the power button, the time gap between the initial gray screen and the gray screen that displays the apple and the startup circle got substantially longer. However, that computer will boot and work normally.

2. Recently, a progress bar (never seen before) appeared below the startup circle. My Mac Pro has never displayed this progress bar when starting up.

3. The newly displayed progress bar (since the very first time that it showed up) consistently disappeared at about 1/3 of the way and then suddenly reappeared after which the Mac Pro will shut down.

Upon pressing the power button, all the right noises can be heard. I tried zapping the PRAM but no good.

Any ideas as to what is going on and/or a possible fix?

Many thanks for your time and effort.

Jacobo

Mac Pro, Mac OS X (10.6.8), 3.2 GHz Nehalem (4-core), 18 GB RAM

Posted on Feb 24, 2018 12:56 PM

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User profile for user: Tesserax
Tesserax
User level: Level 10
148,239 points

Posted on Feb 24, 2018 1:02 PM

Please try the following, in order. Stop at the step where the issue is resolved:

  1. Reset your Mac's SMC.
    • Reset the System Management Controller (SMC) on your Mac- Apple Support
    • Fans, keyboard backlight, status indicator, battery indicator, display backlight, power button, close/open the lid, sleep or shut down, battery doesn't charge, MagSafe indicator light incorrect status.
    • Hold down the <shift><control><option> keys, and then, press the power button. Hold all of them for, at least, 10 seconds.
  2. Boot up your Mac in Safe Mode.
  3. Boot up your Mac in Recovery or Internet Recovery Mode.
    • About macOS Recovery- Apple Support
    • When at the initial Recovery Mode screen, select the Disk Utility option.
    • Run Disk Utility > First Aid to verify the startup disk's integrity.
  4. Boot up your Mac in Single-User Mode.
    • How to start up your Mac in single-user or verbose mode- Apple Support
    • At the command prompt, type: /sbin/fsck -fy <return>

      If fsck makes any repairs, you will get a message that says: Files System was modified. If you do, run fsck again until the "The volume <volumename> appears to be OK."

    • Type reboot at the prompt to exit Single-User Mode.
  5. Run either Apple Hardware Test (AHT) (pre-2013 Macs) or Apple Diagnostics (2013+ Macs) to uncover any hardware issues with your Mac.
  6. Make a Genius Bar appointment at your local Apple Store.
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User profile for user: Tesserax
Tesserax
User level: Level 10
148,239 points

Feb 24, 2018 1:02 PM in response to Jacobo

Please try the following, in order. Stop at the step where the issue is resolved:

  1. Reset your Mac's SMC.
    • Reset the System Management Controller (SMC) on your Mac- Apple Support
    • Fans, keyboard backlight, status indicator, battery indicator, display backlight, power button, close/open the lid, sleep or shut down, battery doesn't charge, MagSafe indicator light incorrect status.
    • Hold down the <shift><control><option> keys, and then, press the power button. Hold all of them for, at least, 10 seconds.
  2. Boot up your Mac in Safe Mode.
  3. Boot up your Mac in Recovery or Internet Recovery Mode.
    • About macOS Recovery- Apple Support
    • When at the initial Recovery Mode screen, select the Disk Utility option.
    • Run Disk Utility > First Aid to verify the startup disk's integrity.
  4. Boot up your Mac in Single-User Mode.
    • How to start up your Mac in single-user or verbose mode- Apple Support
    • At the command prompt, type: /sbin/fsck -fy <return>

      If fsck makes any repairs, you will get a message that says: Files System was modified. If you do, run fsck again until the "The volume <volumename> appears to be OK."

    • Type reboot at the prompt to exit Single-User Mode.
  5. Run either Apple Hardware Test (AHT) (pre-2013 Macs) or Apple Diagnostics (2013+ Macs) to uncover any hardware issues with your Mac.
  6. Make a Genius Bar appointment at your local Apple Store.
Reply
User profile for user: Jacobo
Jacobo Author
User level: Level 2
228 points

Feb 24, 2018 3:40 PM in response to Tesserax

Hi Tesserax,


Good news! Although none of the suggestions you proposed worked, the fact that safe mode booting checks the directory of the startup volume got me thinking. A recent Disk Warrior run revealed some issues with my system's disk directory. So I stated my Mac Pro from an external system's disk backup drive and used Disk Warrior to replace the damaged system's directory.


Many thanks for taking the time to try to help me; I sincerely appreciate it.


Kind regards,


Jacobo

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Mac Pro Shuts Down During Startup.

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