Mac Pro Mid 2012 Reformat and MacOS Reinstall Issue

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Mac Pro Mid 2012 Reformat and MacOS Reinstall Issue

Hi, I am in the process of reformatting my Mac HD and doing a clean OS install on a Mac Pro mid 2012. I was running OSX 10.13 High Sierra prior to doing the reset. I erased my Macintosh HD via Disk Utility from the Recovery Mode menu and then reinstalled the OS (High Sierra). The reinstall neared completion when I was presented with the message:

"Could not create a preboot volume for APFS"

My Mac HD is formatted as APFS. When I run First Aid I receive this message:

I am unable to access the option to install the original OS (Mountain Lion) that the MP shipped with. Any suggestions? Thanks in advance for the help.

Mac Pro

Posted on May 29, 2021 8:02 AM

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Answer 1

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BDAqua

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May 29, 2021 8:55 AM in response to burnm

You have to choose the whole drive, not a container.

In Disk Utility do CMD+2 key or in the View Menu choose Show all devices, then pick the top left icon in the sidebar, Might be SanDisk in your setup.

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Answer 2

BDAqua

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May 29, 2021 8:11 AM in response to burnm

Older Macs need to have the Drive formatted MacOS Extended for the Install of 10.13.6 to take place.

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Answer 3

BDAqua

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May 29, 2021 11:53 AM in response to burnm

What is disk 0 & dusk1 ?

diskutil list

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Answer 4

BDAqua

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May 29, 2021 9:17 AM in response to burnm

Are you booting from the Restore Partition?

2. Decide whether to erase (format) your disk

If you need to erase your disk before installing macOS, select Disk Utility from the Utilities window, then click Continue. You probably don't need to erase, unless you're selling or giving away your Mac or have an issue that requires you to erase. Learn more about when and how to erase.

3. Install macOS

After starting up from macOS Recovery, follow these steps to install macOS:

Choose Reinstall macOS (or Reinstall OS X) from the Utilities window.
Click Continue, then follow the onscreen instructions to choose your disk and begin installation.
If the installer asks to unlock your disk, enter the password you use to log in to your Mac. If it doesn't see your disk, or it says that it can't install on your computer or volume, you might need to erase your disk.

Please allow installation to complete without putting your Mac to sleep or closing its lid. During installation, your Mac might restart and show a progress bar several times, and the screen might be empty for minutes at a time.

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Answer 5

BDAqua

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May 29, 2021 9:49 AM in response to burnm

I hope the SSD didn't get fried, but in Restore mode's Disk Utility, try CMD+ E keys to eject or unmount the drive.

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Answer 6

burnm Author

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May 29, 2021 9:27 AM in response to BDAqua

I am booting from macOS Recovery. When I power on without using the key command for macOS Recovery I get this screen:

I started this process last night. A thunderstorm storm started as I was halfway through. Unfortunately, my battery back-up power supply was not working, so I lost power several times during the installation process.

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Answer 7

burnm Author

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May 29, 2021 10:54 AM in response to BDAqua

Yes, that is correct. I highlighted the whole drive, but there is no option to unmount or eject.

I do have an external drive that I can boot from.

No, I am not familiar with Terminal, but am willing to poke around. On the other hand, I may just run up the street and purchase a replacement SanDisk SSD.

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Answer 8

burnm Author

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May 29, 2021 2:39 PM in response to burnm

I bought a new SSD and swapped it out with the old one. Upon startup, a flashing folder with a question mark shows and never goes away. Computer won't boot in macOS Recovery mode or Internet Recovery mode. None of the key commands seem to work. Do I need to create a bootable USB drive for this issue?

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Answer 9

burnm Author

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May 29, 2021 8:25 AM in response to BDAqua

Thanks @BDAqua. These are the only options available for the Mac HD:

When I click on the container I get these options followed by this error message:

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Answer 10

burnm Author

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May 29, 2021 8:51 AM in response to BDAqua

Do I need to delete the Mac HD volume and re add it?

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Answer 11

BDAqua

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May 29, 2021 8:56 AM in response to burnm

No, see my previous post just a minute ago...

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Answer 12

burnm Author

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May 29, 2021 9:04 AM in response to BDAqua

I tried that earlier and received this message when trying to format SanDisk to Mac OS Extended (Journaled):

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Answer 13

burnm Author

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May 29, 2021 10:02 AM in response to BDAqua

I can unmount the Mac HD volume, but I can't unmount the whole drive. CMD E doesn't work and the "Mount" button is greyed out with no option to unmount.

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