Mac Pro 5,1 won't open Boot menu

I have just moved all my projects to shiny new MacBook Pro M1 Pro and plan to sell my trusted Mac Pro... To create a clean macOS High Sierra installation I've erased drive in disk utility. But when selecting Install new macOS it's window's 'shut down' button is greyed out - so I can't take that route.

Tried installing from USB drive but power/alt sequence does not progress.

On my MacBook Pro (Intel) High Sierra, I used a USB HS installer and created an HS installation on a sata ssd (docking station), hoping I could connect to my MP and it would run. Unfortunately another nonstarter.

My computer knowledge is fairly basic so I hope someone can point me in the right direction.

PS: I was able to install HS from a Time Machine backup and everything ran as expected, but I'm stuck with all my personal data on there...

Thanks in advance,

Dave

Mac Pro, 10.12

Posted on Sep 20, 2022 12:14 PM

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Le Batch Author

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5 points

Posted on Oct 3, 2022 12:17 PM

I thought I had successfully installed High Sierra on sata ssd, (via MBP). Connected it up in MP but still couldn't boot into it. No key command options worked. After a couple of days of trying Command+R my MP finally booted into the external CCC backup - I put the drive into a different usb slot and it worked... it had worked in previous slot before.

Installed OS on HD from backup... I hoped to boot up in recover mode and then do clean HS install to ssd from usb installer. but MP still wouldn't boot.

The issue turned out to be the ssd formatting. When erasing drive I had used APFS, it should have been macOS Extended. Although HS uses APFS, the MP 5,1 shipped with Sierra - which is macOS Extended. Now, with the reformatted ssd I booted into Recovery Mode and from there reinstalled Sierra from Apple. So all ended well...

I've never come across an intermittent USB connection before, (CCC Backup drive), but it certainly muddied the waters when trying to diagnose where my problem lay - two unconnected issues occurring simultaneously...

Thanks for the trouble you've taken to steer me through all of this, much appreciated... I've now got a clean Mac Pro macOS Sierra I can put up for sale.

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Mac Pro 5,1 won't open Boot menu

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