Can you run an older macOS from a bootable drive?

d_gomaiste

macrumors member
Original poster
Mar 18, 2016
35
0
Hey all,

I have a 2015 iMac that shipped with Sierra. I’ve got a very important project coming up where I need to run Pro Tools 10, which is completely unusable on anything past Yosemite.

Would it be possible to create a bootable USB drive that has Mavericks or Yosemite installed and boot from there?

If so, how would I do this?
 

vertical smile

macrumors 601
Sep 23, 2014
4,018
5,216
I don't think you can run Yosemite on the Late 2015 iMacs. I think they launched with El Capitan, which is most likely the oldest OS they can natively support. Maybe it can use Yosemite, it might be worth a try if you have no other option.

You can do internet searches on where to find older Mac OS versions, but the easiest is if you have an older Mac. Which, I assume you don't because you probably wouldn't have this issue.
 

casperes1996

macrumors 601
Jan 26, 2014
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Horsens, Denmark
If the hardware came out after the OS, then the older OS will not have drivers for the hardware in the newer Mac (typically). So the answer on that front is no.
You can however still run the older OS within a virtual environment like VMWare, Parallels and the like.
 

d_gomaiste

macrumors member
Original poster
Mar 18, 2016
35
0
If the hardware came out after the OS, then the older OS will not have drivers for the hardware in the newer Mac (typically). So the answer on that front is no.
You can however still run the older OS within a virtual environment like VMWare, Parallels and the like.
How would I go about doing this? I thought Parallels was only for running Windows on Mac. Didn’t realize it had other uses.
 

chrfr

macrumors G3
Jul 11, 2009
8,293
2,589
How would I go about doing this? I thought Parallels was only for running Windows on Mac. Didn’t realize it had other uses.
You won't be able to run Pro Tools successfully in a virtual environment, so I wouldn't even bother.
 

d_gomaiste

macrumors member
Original poster
Mar 18, 2016
35
0
Yeah, I figured this would be a bit convoluted, since it involves actual audio hardware.

Back to my original question — I’m not trying to install Mavericks or Yosemite on the actual iMac itself, and I DO have installers for both OSes. I’m wanting to know if I can use an external HD or USB key to create a bootable drive that has Mavericks installed, and then boot into that with my new iMac.
 

Brian33

macrumors 6502a
Apr 30, 2008
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USA (Virginia)
It doesn't matter whether the older OS is installed on an external drive or an internal drive -- it will either work in both scenarios or not work in both scenarios. So I think you're out of luck running Yosemite directly on the machine. However, as pointed out, it will likely run in a virtual machine. I have the same iMac as you do, and can successfully run Mountain Lion within a VirtualBox VM.

I'm not sure if chrfr's comment about not being able to run Pro Tools 10 in a VM is absolutely true. It would be very laggy, for sure, but it might work well enough for what you need to do. It can be a bit of a pain in the neck setting up a VM, though, so considering that plus the performance issues, you might be better off looking for a used machine that would run Yosemite.
[doublepost=1552583186][/doublepost]Sorry, just noticed you need to use actual audio hardware. Yeah, I wouldn't bother trying a VM for that...
 

StellarVixen

macrumors 68020
Mar 1, 2018
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Earth
As many have already said, older versions of Mac OS do not have necessary compatible kernel extensions for newer Mac models. Therefore, there is no chance to run anything lower on bare metal than the version that your Mac came with.


Your only option is virtualization.
 

DeltaMac

macrumors G3
Jul 30, 2003
9,605
2,352
Delaware
Another option would be getting a version of ProTools that is actually useful to you.
It's a shame when you are forced to use an older version of pro-level software, then it's on you to figure out how to get the job done.
Protools is, unfortunately, software that is tightly tied to both hardware and OS X version in use, which is a big limiting factor here. Old software, in this case, needs hardware contemporary with that ProTools version, so you can easily run the older OS X version that software supports. Avid, for years, has had extensive compatibility listings (which can be totally confusing) that should result in a working ProTools work station.
 

casperes1996

macrumors 601
Jan 26, 2014
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Horsens, Denmark
Yeah, I figured this would be a bit convoluted, since it involves actual audio hardware.

Back to my original question — I’m not trying to install Mavericks or Yosemite on the actual iMac itself, and I DO have installers for both OSes. I’m wanting to know if I can use an external HD or USB key to create a bootable drive that has Mavericks installed, and then boot into that with my new iMac.

Just thought of something that might (might not?) work for you. If you can get your kernel extensions relevant for the hardware in your machine into the kext-folder for Yosemite, Yosemite might actually be able to boot on your machine. Essentially backporting drivers to the older OS
 

chrfr

macrumors G3
Jul 11, 2009
8,293
2,589
Just thought of something that might (might not?) work for you. If you can get your kernel extensions relevant for the hardware in your machine into the kext-folder for Yosemite, Yosemite might actually be able to boot on your machine. Essentially backporting drivers to the older OS
It’s impossible to use Yosemite on the late 2015 iMac. There’s no way to get drivers from a later OS to load in the earlier one.
[doublepost=1552617314][/doublepost]
Hey all,

I have a 2015 iMac that shipped with Sierra. I’ve got a very important project coming up where I need to run Pro Tools 10, which is completely unusable on anything past Yosemite.

Would it be possible to create a bootable USB drive that has Mavericks or Yosemite installed and boot from there?

If so, how would I do this?
Exactly which model iMac do you have? The mid-2015 27” retina iMac can run Yosemite, but none of the late 2015 models can.
 

d_gomaiste

macrumors member
Original poster
Mar 18, 2016
35
0
It’s impossible to use Yosemite on the late 2015 iMac. There’s no way to get drivers from a later OS to load in the earlier one.
[doublepost=1552617314][/doublepost]
Exactly which model iMac do you have? The mid-2015 27” retina iMac can run Yosemite, but none of the late 2015 models can.
Late 2015, unfortunately.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,444
5,660
You cannot boot a Mac with a version of the OS that is OLDER THAN the version that the Mac shipped with.

This is a hard-n-fast rule of Mac'dom.
There are very, very few exceptions.

If you need to know exactly which version of the OS a Mac shipped with, I believe you can check this at everymac.com.

The only other "workaround" is to use some kind of "virtual machine", as other posters have explained above.