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PrittStick

macrumors newbie
Original poster
Jan 14, 2020
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0
I've searched everywhere for the answers to these questions! I'm stuck. Please help.

Firstly, I'm partitioning my 1TB SSD to allow me install Mountain Lion, Yosemite, and Catalina on the same drive. I'd like all my files to be on the Catalina partition, apart from specific software which only function on Mountain Lion and Yosemite. Would it create a slower performance if the software is having to access files that are saved on another partition?

Secondly, if I use Disk Utility to clone my old HDD to the SSD will it copy the free space? If not, how can I clone the HDD without cloning the free space?

There was a third question but I've forgotten what it is..

Anyway - Thanks for reading :) Any advice is greatly appreciated
 

timidpimpin

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Nov 10, 2018
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You shouldn't be keeping all your data on any OS drive in the first place. Over time it will contribute to a less healthy OS software-wise. What I would do is just make a data only partition as well. Most people only typically need 40-80GB for their OS and apps. I would create 3x 80GB partitions for the 3 OS, and have a 4th partition with the rest of the space.

Here's a potential issue you could have though, but I'm not sure. That is that Catalina can only install on an APFS drive/partition, and I'm not sure if you can mix APFS and HFS pattitions on the same physical drive. I say that because Mountain Lion and Yosemite don't support APFS, so you will have to use HFS.
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,348
12,464
My opinion only, but...

I would not partition and install different OS's on a single SSD.

Rather, I'd get a small SSD for each OS, and set them up that way.

I WOULD NOT attempt to install Catalina on ANY drive that has another OS on it.

Again, my opinion only.
 
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timidpimpin

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My opinion only, but...

I would not partition and install different OS's on a single SSD.

Rather, I'd get a small SSD for each OS, and set them up that way.

I WOULD NOT attempt to install Catalina on ANY drive that has another OS on it.

Again, my opinion only.

This is goot advice OP. Catalina is a new type of beast, with much different prerequisites than all previous macOS. Best to not mix it with others.

Also... is there a legitimate reason you need both Mountain Lion and Yosemitie? If not, then I suggest you keep it to one older version if you can. IMO El Capitan is a very good version to bridge between old and new. It's an advancement on the Yosemite code also. It's like you want to run Lion over Mountain Lion or Leopard over Snow Leopard or Sierra over High Sierra. You see my point?
 

PrittStick

macrumors newbie
Original poster
Jan 14, 2020
5
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Thanks for the replies guys!

I need Mountain Lion to run Avid Pro Tools 10 and I need Yosemite to run Avid Pro Tools 11. That's pretty much all. Obviously I'd also like the latest OS to run everything else. I wanted all of my files in one place though.

Is the consensus that I should have multiple hard drives? That seems really inconvenient but I do have a 750GB HDD that fits into the CD drive space (it's a 2012 MacBook Pro). I just wanted to utilise my 1TB SSD so that I made the most of the speed improvements.
 

timidpimpin

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I have had very successful experiences with running older apps on El Capitan. Some as old as 2006 - the Tiger days. Also, I'm noticing a trend with you running things redundantly. Did Avid 11 drop things you liked in 10?

I think the best overall plan for you is to make sure you have everything backed up first, and then try it the way you wanted to originally and see if everything works properly. But if it doesn't go well then you need to figure out alternative ways.

But please... heed this advice. If you're going to try running 3 OS on the same physical drive, don't keep any personal files on any of the boot partitions. SSD's that boot OS's will be the most healthy when it's just the OS and apps combined with at least 50% free space on the boot partition/drive.

Do the above and your OS's will have a long and healthy life with a much lower chance of bit rot. Then on whatever drive you keep personal data and downloads on you can organize things by OS to find them easily. I even go as far as having my browser download to a non-boot drive. All those partitions will potentially give you enough headaches, so you should go with ultimate stability with everything else if you insist on partitions.

Also, I'm not even sure you can format just a partition to APFS, which Catalina requires, because in the Catalina installer disk utility I had to format the entire volume.
 
Last edited:

MarkC426

macrumors 68040
May 14, 2008
3,556
1,987
UK
My opinion only, but...

I would not partition and install different OS's on a single SSD.

Rather, I'd get a small SSD for each OS, and set them up that way.

I WOULD NOT attempt to install Catalina on ANY drive that has another OS on it.

Again, my opinion only.
Additional to the above, I would not be using your main (triple system drive.........?) as a scratch disk while working in Pro Tools.
Is it not an option to upgrade your Pro Tools and just have one OS?
It would be better then to have an external ssd for scratch/recording.
 

gilby101

macrumors 68020
Mar 17, 2010
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Tasmania
I need Mountain Lion to run Avid Pro Tools 10

If it wasn't for the mention of Avid, I would strongly recommend configuring the whole disk for Catalina and running the other macOSes in virtual machines. Whilst VMware Fusion will connect USB devices to virtual machines, I don't know how well this works with audio devices. I would ask for advice on this before considering your multiple boot scenario.

But coming back to your questions:

I would create 3x 80GB partitions for the 3 OS, and have a 4th partition with the rest of the space.

That is what I would do, too. But a bigger partition for your most used macOS (Catalina).

Each partition can be formatted as required. HFS+ for old macOs and APFS for Catalina.

Doing this is not trivial. You will bootable installers (on USB sticks). I suggest you create all the partitions with the first install. But, be warned, it will not be easy to adjust the size of the partitions later.

Also, I'm not even sure you can format just a partition to APFS, which Catalina requires, because in the Catalina installer disk utility I had to format the entire volume

I think you are confusing partitions and volumes. The physical disk is divided into partitions. For HFS+ the partition is simply formatted as HFS+. For Catalina, its partition has an APFS 'container' which holds volumes (system, data, recovery and vm). Disk Utility is confusing (hides the truth) unless you enable View -> Show All Devices.
 

PrittStick

macrumors newbie
Original poster
Jan 14, 2020
5
0
Well.. I’m sufficiently confused ?

I have a couple more questions. Firstly, if I have Avid Pro Tools installed on Mountain Lion (HFS+), but it has to access the files saved on my “personal files” Catalina partition (APFS); is this even possible?

Secondly, I previously set up the SSD with the three partitions before I knew about all these differences, but I’ve only installed Catalina. I do think the other two partitions are HFS+ though, and they are currently empty. I was using it on a 2013 13” MacBook Pro. I have now repaired my 2012 15” MacBook Pro, but when I try and swap the SSD over, it won’t load the Catalina partition. I turn the MacBook on and all I see is a folder symbol with a question mark inside it.

Any idea what’s going on?! It still works fine when I swap it back to the 13” MacBook Pro. There is nothing wrong with the hard drive cable either because the 15” MacBook Pro will boot its original HDD without any problem.

o_O
 

MarkC426

macrumors 68040
May 14, 2008
3,556
1,987
UK
What OS was on the 15inch, it may need a firmware update, which is done during the OS install.

Go to about this mac, system profiler to see fw version.
 

PrittStick

macrumors newbie
Original poster
Jan 14, 2020
5
0
Ahh ok thanks. Here’s the info I could find:
 

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PrittStick

macrumors newbie
Original poster
Jan 14, 2020
5
0
Well chaps.. That was a rigmarole. I've described below what happened (for future reference), but I'd like to ask another question first.

A few of you said I should install my files on a separate partition from my OS partitions. If I do this, where do I install the rest of my software? Should I install software on the file partition or the OS partitions?


And now for the story..

I replaced my HDD with a spare HDD I had and tried to install Catalina, booted from a USB drive. I was hoping this would upgrade my firmware, but it only got through half of the install and then stopped. The install continued when I plugged that spare HDD into my other MacBook Pro (which has already installed Catalina previously).

I decided to install an interim OS before trying to install Catalina again. I upgraded my Yosemite partition in my original HDD to El Capitan. I then left my original HDD in place, but installed Catalina on the spare HDD plugged into a USB port. This finally worked and I can now use my SSD with Catalina installed on my original MacBook Pro.
 
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