Running Multiple OS on a mid 2012 Mac

Question

Running Multiple OS on a mid 2012 Mac

I have a mid 2012 Mac with the option of booting into High Sierra or Mojave. I recently added drives with Yosemite and El Capitan but I am unable to boot into either. According to my various searches El Capitan should run. But strangely, I am told that Yosemite needs a Late 2013 Mac Pro. Yosemite precedes all the other operating systems yet needs a later Mac Pro to run it? I transferred the Yosemite drive from a 2009 Mac Pro where it would happily run.

If I try to boot into either Yosemite or El Capitan I get a blank screen/no video output. So I have to hold in the power button to restart. Sometimes it takes a long press insinuating that something somewhere has loaded and on other occasions it powers off straight away.

I have three video outputs. 2 x HDMI and 1 x DVI. I swapped them about after booting to see if I had a signal anywhere.

Once I had chosen to boot from either of the new OS's, to get back to an OS I could boot into I had to remove the drives as it would seem that the machine kept trying to do what I asked it to and failing.

I also tried powering up while pressing the option key to get to the various operating systems that way. No joy.

Both Yosemite and El Capitan are on 3.5 hard drives and I have Yosemite on an SSD if it makes a difference. But I shouldn't imagine it does. I have tried both Yosemite drives.

Mac Pro, macOS 13.6

Posted on Jul 7, 2024 3:11 AM

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Answer 1

Jul 7, 2024 6:26 AM in response to ThisNameIsntTakenIsIt

<< If I try to boot into either Yosemite or El Capitan I get a blank screen/no video output. >>

what graphics card is installed? some require much newer MacOS than the default MacOS 10.16 that shipped in the box.

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Answer 2

Jul 7, 2024 1:37 PM in response to ThisNameIsntTakenIsIt

third party information suggest Drivers for the RX 580 were included in 10.12.6 and later.

So not getting a picture with earlier MacOS is likely down to no display driver.

The 5870 drivers first appeared in 10.6.5 and later.

If you install your emergency GT120 that you always have on hand, those older versions will work fine.

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Answer 3

Jul 7, 2024 2:36 PM in response to Grant Bennet-Alder

Ok, that explains it. Many thanks. But, unfortunately, even if I had an emergency GT120, there is no room left on the board. When I slotted in the Yosemite SSD I removed a USB 3 card which, when installed, I had to tease away from the RX580 fans with a plastic washer. Looking at the screw heads on the GT120 I won't be able to fit it next to the RX580. I will get one and see if I can move stuff around on the board to make it all fit and use the 3.5 drive Yosemite install.

I also have the original GEforce GTX 780 that came with my old mac. Still a chunky beast but only one fan towards the back of the card. The machine will have a lighter GPU load now so that could go back if it helps. We will see.

Thinking about that. I will see if I can find out if the old versions had drivers for the GTX 780. That could solve it.

If not and before I buy the GT120 and start moving stuff around on the board, I assume there is no other way. Could I put the drives back in the old machine, boot up the old versions and install drivers for the RX 580/GTX 780 before sticking them back in the new machine? Or any other possible solutions?

Many thanks for you help either way.

Phil

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Answer 4

Jul 7, 2024 2:55 PM in response to Grant Bennet-Alder

I have searched for GPUs supported by Yosemite and El Capitan and seen some close matches for the GTX 780 but not exact. I suppose that as I have one and I know it works with the later versions I may as well try it and find out. I'm just a bit jumpy messing about with the logic board too much. There you go.

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Answer 5

Jul 7, 2024 4:59 PM in response to ThisNameIsntTakenIsIt

Mac-firmware GT120 is a one-slot card, works in any slot and requires NO aux power. There are more than 80 on US eBay at this writing and most are under US$30.

another possibility os to install a different MacOS in a virtual machine like VirtualBox.

Why do you need an actual running version of each of these versions of MacOS? They are all very similar. In all cases I can think of, you don't need to run their MacOS to read their files.

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Answer 6

Jul 8, 2024 2:46 PM in response to Grant Bennet-Alder

I tried the GTX 780 that I swapped out for the RX 580 and bingo. All the versions run. I need to boot with the option key to get back to Mojave/High Sierra from the older systems but small price to pay. So all good. Thanks for your help.

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Answer 7

Jul 7, 2024 11:13 AM in response to Grant Bennet-Alder

Its a Radeon RX580 8gb. The early 2009 machine I transferred the drives from has an AMD ATI Radeon 5870 1gb

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