Mac Pro shuts down during startup.

Question

Level 2

228 points

Mac Pro shuts down during startup.

Hi there,

Here are the sequence of events that eventually led to my PM'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 gray apple and the startup circle got substantially longer.

2. eventually, a progress bar (never seen before) began to appear below the startup circle. My PM back has never displayed this progress bar when starting up.

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

Upon pressing the power button, all the right noises can be heard.

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

Many thanks for your time and effort.

Jacobo

<Re-Titled by Host>

PowerMac, Mac OS X (10.6.8), 18 GB RAM

Posted on Feb 22, 2018 3:02 PM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

140,261 points

Feb 25, 2018 8:31 AM in response to Jacobo

When booting up, a Blob of software is initially loaded from a "magic" location on the drive. It is initialized, and it draws the solid Apple (that Apple in NOT in the Mac's ROM). If you see the Apple, your drive is not dead.

The next step requires Many files by name. The File System is initialized, and the drive is Mounted. If the drive is damaged, it cannot be mounted, so the progress bar is stretched for an about five-minute "Repair Disk".

At the end of one pass of repair Disk, the Mac attempts to Mount the drive again:

-- If it passes, Boot-up continues

-- If it fails, your Mac can do nothing more, so it powers off.

So your drive is damaged, and you need to run Disk Utility and attempt to repair it again until it comes clean or is hopelessly stuck. The only source of Disk Utility for a 10.6.8 Mac is the Installer/Utilities DVD. (in 10.7 and later, there is a Recovery partition on the Boot drive that could be used instead.)

You need to BOOT from an Installer/Utilities DVD, select Disk Utility from the Utilities menu that will eventually show up, and run Repair Disk. run it again until the drive comes clean or is hopelessly stuck.

If stuck, DO NOT Erase your Disk Unless/Until you post back here for some alternatives.

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Answer 2

Jacobo Author

Level 2

228 points

Feb 25, 2018 11:17 PM in response to Grant Bennet-Alder

Hi Grant,

Thanks so much for your response. I was able to boot from an external back-up system drive from which I ran Disk Warrior. The directory of the boot drive was repaired and replaced and all is good now.

However, I am noticing an unusually long time delay between the startup chime and the appearance of the "solid" apple. After the chime, the screen turns gray and (up to) 45 seconds later the apple appears. Perhaps the drive is beginning to fail.

Thanks again!

Jacobo

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Answer 3

Jacobo Author

Level 2

228 points

Feb 25, 2018 11:20 PM in response to kahjot

Hi kahjot,

Thanks so much for your response. I was able to boot from an external back-up system drive from which I ran Disk Warrior. The directory of the boot drive was repaired and replaced and all is good now.

The only system installed in my Mac Pro is 10.6.8 and I am always in control of what is installed in my computers.

Thanks a lot for taking the time to help me.

Jacobo

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Answer 4

Jacobo Author

Level 2

228 points

Feb 26, 2018 10:12 PM in response to Grant Bennet-Alder

Hi again,

That was it; no startup disk was actually highlighted. Upon clicking on my drive, the startup process came back to normal.

Thanks a lot for the observation.

Jacobo

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Answer 5

kahjot

Level 4

2,463 points

Feb 25, 2018 5:45 AM in response to Jacobo

How many OS versions are installed? The progress bar sounds like Yosemite or later, not Snow Leopard. You could also see that if you had not prevented the App Store from installing major upgrades automatically, and something is trying to install itself. More details about your system would help.

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