Recommendations on how to set up a new install alongside Mojave volume?

gadgetfreak98

macrumors regular
Original poster
Feb 6, 2009
133
39
Hi all,

Now that the public beta is out, I'm thinking I would like to mess around with a new install on a separate volume from my healthy Mojave startup volume. That way I can test it out, without giving up on the solid Mojave setup I have.

Are there any precautions I need to be aware of? I am on a Mac Mini 2018 and, given it's APFS, was just going to install on a separate partition / volume on the internal drive (as I have sufficient space). But I definitely do NOT want to accidentally upgrade my Mojave setup.

Should this be done on an external TB3 drive? Any other recommendations? Obviously, the benefit of internal is the SSD speed.

Thanks!
 

alexclst

macrumors member
Dec 24, 2007
52
18
Saint Paul, MN
Catalina is on an APFS volume on a secondary Mac for me. That works fine. During the install just be sure to select “show all disks” and choose the volume you just created. Your Mojave system should stay just fine. Note that Catalina will split that volume into two, one read-only with the system files, and the read-write data volume. So you will end up with 3 volumes altogether.

The one caution, albeit a small one, is that on some Macs Catalina brings new firmware. While this shouldn’t affect the Mojave system detrimentally, that is one reason why I both use a secondary Mac (in my case, my laptop versus the desktop I use daily), and separate APFS volumes.
 

gadgetfreak98

macrumors regular
Original poster
Feb 6, 2009
133
39
Great. Thank you both. Figured it was relatively straightforward, but wanted to make sure there were not known pitfalls/issues.

Appreciate it.
 

jdasikainen

macrumors 6502
Mar 4, 2016
353
64
Bald Knob Arkansas
yup typing now in Catalina playing with the new features and its rock solid now one thing you will want to do after you install it is go into your Majove software update to remove the Catalina software updater so it doesn't nag u to upgrade to the beta lol
 

gadgetfreak98

macrumors regular
Original poster
Feb 6, 2009
133
39
Yes, I figured I would need to do that... however, I'm stuck on the Cannot Verify MacOS error.

I first tried to install Mojave onto the new partition/volume, thinking that way I would never put the beta profile on my regular startup drive.

That failed with the Cannot Verify error, so I went ahead and used the Beta update tool. Went through the download of Catalina, but got to the same exact error -- cannot verify.

I'm on with AppleCare, who seems pretty clueless... any ideas?
 

gadgetfreak98

macrumors regular
Original poster
Feb 6, 2009
133
39
I screwed something up here. Add a new APFS volume on my internal drive. Finally got Mojave installed on that via recovery mode. Then did the Catalina install on that volume so I didn’t have the beta profile on my main Mojave volume.

Now nothing starts up properly. I have tried to redesignate my Mojave drive as the startup. But that seems to fail.

I’m trying in Recovery Mode again to delete the Catalina volume(s) from the drive to go back to where I was. But they will not delete. I think this may be because recovery mode is off the Catalina volumes?

Odd that I cannot get the Mojave volume to be the proper startup even though I can select it.

I’d ease? Thanks!
 

Fishrrman

macrumors P6
Feb 20, 2009
17,209
5,554
My opinion only, but if you want to try Catalina at this stage of the game, DON'T try installing it on the same volume as your "mission critical" copy of the OS (the one you depend on from day-to-day).

Use a PHYSICALLY SEPARATE drive instead.
Either SSD or HDD (HDD works, but will be slow with much disk thrashing).
 

gadgetfreak98

macrumors regular
Original poster
Feb 6, 2009
133
39
Yes, sadly, I did not do this. Was able to get Catalina up and running this morning, but could not get my Mojave volume to start up. Think I'm going to have to start from my SSD clone of my startup drive, wipe the internal completely, and clone back over to the internal Mac HD. Hopefully that brings thing back to normal!

Then -- and only if I'm feeling bold -- will I do as you suggest and use an external SSD to try Catalina. I have an NVMe drive from my now defunct Mac Pro that reads at about 500+ via TB3. Should be good to get a feel.
 

gadgetfreak98

macrumors regular
Original poster
Feb 6, 2009
133
39
So I was able to get my Mojave installation up and running again -- although frankly, how I got there, I'm not sure. But I used the opportunity to delete the Catalina volumes on my internal SSD (even though I had gotten it to work -- once). Oddly, there were two Catalina "Data" volumes. I suppose one was created when the first attempted install didn't work.

In any event, lesson learned. I am not going to re-install Catalina on my internal SSD. I may try again on my external NVMe.

One lingering concern I have... Would Catalina have replaced the Recovery Partition on my startup drive with the Catalina version? I know, from using terminal, that the disk1s3 volume is the recovery -- but I cannot tell if it is Catalina or Mojave. Is there a way to independently source and install the proper Mojave software if it is Catalina?

Thanks.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,209
5,554
"One lingering concern I have... Would Catalina have replaced the Recovery Partition on my startup drive with the Catalina version?"

Try booting to the recovery partition, and tell us the results you get...
 

gadgetfreak98

macrumors regular
Original poster
Feb 6, 2009
133
39
It seemed it tried to go into internet recovery with the spinning globe. But then it failed. I got an error with an exclamation mark through the globe.