Can I run two (2) versions of Mac OS?

[OLDTMR]

I have a Mac 27" Retina (2017) with 64 GB Memory and I'm running Mojave because I need to run photoshop CS6 and I refuse to go the subscription route. Little by little, I'm seeing some drawbacks, mostly it seems with Safari and Apple Mail. I'm a retired designer and I don't need Photoshop every day. So what I was wondering was could I somehow run some kind of dual boot setup where I can update to the latest version of Mac OS for my everyday browsing and mail use, and then have a way to call up my old version of Mojave so I can use Photoshop? Do I need to add an external drive where the new or old OS works from? My Mac has the original internal 250GB SSD root drive, and I have an external 2TB USB Fantom drive where I store everything. The SSD has about 90GB free, is that enough to fit an additional version of OS or do I need to get an external SSD? Is there a way to mirror my current drive on to a 1TB internal drive without any hiccups? Any help on how to do this... if its even possible... would be appreciated. TIA-Mike

 

[rm5]

Hi! Yes, you can dual-boot a newer version of macOS. However, if I were you, I would do it on an entirely new external SSD. You'll need to download the newer version of macOS - I'd go for at least macOS Ventura or newer. There is an Apple Support article all about downloading macOS, so you can follow that. Then, run the installer and select your external SSD as a source for the installation. Hope this helps!

 

[OLDTMR]

Hi RM5...

Thanks for reply and suggestion. So I bought a 1 TB Orico SSD and a Quizlab USB4 M.2 NVME enclosure based on youtube reviews. So I was wondering if there is a FAQ somewhere on setting up a new external SSD. The link talks about upgrading your current Mac with a newer OS, doesn't get into downloading a newer OS to a external drive. I'm a little intimidated about plugging in the SSD and don't know how to exactly format the SSD so that I can download a newer OS.

I think you suggested Ventura as a starting point, and then once I have it working (LOL... I hope), I can upgrade to Sequoia 15? So if I get it right, will I be able to switch from the Mojave OS desktop to the Ventura/Sequoia OS desktop with a simple keystroke or will I have to shut down and power up every time I want/need to switch?

Haven't plugged in that drive yet, but it looks like a nice combo. TIA-Mike

 

[saudor]

Your mac supports ventura natively but anything higher will require OCLP which requires disabling SIP since your WIFI is no longer natively-supported.

Ventura still has full app support so it might be a good idea to start with that.

 

[OLDTMR]

I was able to format the new SSD and then download and install Ventura. I haven't booted from the SSD just yet bc I want to make sure I'm doing this right LOL. (I'm a bit nervous) So this is the popup where I'm at right now.

My big question for you experienced guys is how will I select which OS I'd like to boot from? I'm thinking from now on the Mac might be booting always from the new external SSD and maybe the old SSD-250 icon will appear on the desktop and I simply click on that? Or will there be some sort of pop-up that shows the two bootable SSDs and I select which one I want. Another question I have is whether I want to (or even can) import websites and/or Apps, and of course, I think if I continue to use apple mail I can just add the accounts in the new OS right?

Another question I have is why do I see parenthesis with a number when I sometimes logon to some sites with my Mac and/or my iPhone? For instance, I see "iPhone(7)" or something similar with a numbered Mac. Thanks again for the help. I think I'm almost there.-Mike

 

[bladerunner88]

I was able to format the new SSD and then download and install Ventura. I haven't booted from the SSD just yet bc I want to make sure I'm doing this right LOL. (I'm a bit nervous) So this is the popup where I'm at right now.

View attachment 2490236

My big question for you experienced guys is how will I select which OS I'd like to boot from? I'm thinking from now on the Mac might be booting always from the new external SSD and maybe the old SSD-250 icon will appear on the desktop and I simply click on that? Or will there be some sort of pop-up that shows the two bootable SSDs and I select which one I want. Another question I have is whether I want to (or even can) import websites and/or Apps, and of course, I think if I continue to use apple mail I can just add the accounts in the new OS right?

Another question I have is why do I see parenthesis with a number when I sometimes logon to some sites with my Mac and/or my iPhone? For instance, I see "iPhone(7)" or something similar with a numbered Mac. Thanks again for the help. I think I'm almost there.-Mike

Hi OldTmr am in a similar situation: I partioned my Drive and have Mojave on one and Monterey on the other. Ideally you should be able to select the Startup Disk in System Preferences. However to get to initially boot into Ventura you will need to Re-Start or power up holding down the Option key. This will bring up the Startup Manager and you will see a row of Icons representing startup disks, select the one you want either with the trackpad or arrow keys.

As for  Mail yes when you sign in itshould offer to populate your current e-Mail Account info via iCloud.

 

[bladerunner88]

Hi OldTmr am in a similar situation: I partioned my Drive and have Mojave on one and Monterey on the other. Ideally you should be able to select the Startup Disk in System Preferences. However to get to initially boot into Ventura you will need to Re-Start or power up holding down the Option key. This will bring up the Startup Manager and you will see a row of Icons representing startup disks, select the one you want either with the trackpad or arrow keys.

As for  Mail yes when you sign in itshould offer to populate your current e-Mail Account info via iCloud.

feel free to reach out if you have any issues.

 

[OLDTMR]

Hi OldTmr am in a similar situation: I partioned my Drive and have Mojave on one and Monterey on the other. Ideally you should be able to select the Startup Disk in System Preferences. However to get to initially boot into Ventura you will need to Re-Start or power up holding down the Option key. This will bring up the Startup Manager and you will see a row of Icons representing startup disks, select the one you want either with the trackpad or arrow keys.

As for  Mail yes when you sign in itshould offer to populate your current e-Mail Account info via iCloud.

Thx But No Joy Yet. So when I reboot and hold the option key the popup shows both drives and I selected the new OS drive. I get the apple logo, the bar goes across, and I get as far as a screen that says select your country. The arrow keys on the apple keyboard can select up or down that list, but I can't seem to proceed from that window. Plus my Logitech mouse isn't being recognized. Do I need to dig up my apple mouse to make this work? Now when I reboot with the original internal OS, and the main screen comes up I'm seeing these popups.

Should I ignore these and just delete them? Also, once I do get this running is this gonna work like parallels where I can jump back and forth between the OS's? I'm guessing probably not, but wanted to ask that.-Mike

 

[bladerunner88]

Thx But No Joy Yet. So when I reboot and hold the option key the popup shows both drives and I selected the new OS drive. I get the apple logo, the bar goes across, and I get as far as a screen that says select your country. The arrow keys on the apple keyboard can select up or down that list, but I can't seem to proceed from that window. Plus my Logitech mouse isn't being recognized. Do I need to dig up my apple mouse to make this work? Now when I reboot with the original internal OS, and the main screen comes up I'm seeing these popups.
View attachment 2490312

Should I ignore these and just delete them? Also, once I do get this running is this gonna work like parallels where I can jump back and forth between the OS's? I'm guessing probably not, but wanted to ask that.-Mike

Sorry yeah, forgot to mention initially on the first start up your Bluetooth Mouse wont be recognized so use a wired one.
Ignore the Popups - DON'T DELETE THEM Your getting those as part of your Ventura Install which Mojave wont recognize as its a much Newer OS. You can close the dialog BUT DONT Delete them. As an example when am booted into Mojave I have a Disk Icon on my Desktop called "Update" and i also get the incompatible Disk Dialog.

 

[OLDTMR]

Success! Well... about 95% anyway. So I can hold down the Option key while booting and will get the two Mac options, one for Mojave, one for Ventura. That part seems to work just fine. Was also able to add my email accounts to the Ventura side, don't know if I want all the favorites from the past or if they can be migrated to both systems. For some reason, the wireless Logitech MX Master 2S mouse has to be installed as when I boot into Ventura it'll only work with the wired apple mouse. I'm also getting these popups only in the Mojave boot. Are they because Mojave doesn't recognize the Ventura SSD? Is this normal? Another little issue is that my my Windows 11 Pro pc on my network isn't showing up in either OS. I'll have to figure out that issue as I do a lot of graphic file sharing between the Mac and the W11 PC because some programs I use don't have Mac versions.

Thanks again for the help in getting this far, if anyone has thoughts on getting that last 5% fixed, I'l appreciate it.-Mike

 

[bladerunner88]

Hey Mike - I think part of the problem is security in Ventura is more locked down than in previous OS'es, so having to re establish connection to your Logitech makes sense in the installation part you may be asked to approve the Device or something along this lines. Not sure about your PC as I dont do Windows but imaging its some thing similar. Try Connect To Server under the Go Menu and make a note of you PC's IP # first.

TheMojave pop ups are for the reason you stated tho am a little surprised there are so many, maybe try a different port to connect to and or a different cable.

 

[OLDTMR]

Got access across both PC and Mac in the Mojave. Something weird is going on, when I reboot I don't get a menu selection for Mojave or Ventura any more. Sometimes its booting into Ventura, I reboot and it boots right into Mojave. Both go immediately to the different home screens for each. What could be causing the menu to disappear? Do I have to hold down the Option key _EVERY_ time I reboot? I thought this menu would come up automatically. Is there any way to use something like Parallels or whatever to just hit a key and switch back and forth from Mojave to Ventura? Kinda like you would switch to Windows from Mac OS without shutting down and rebooting? Or am I dreaming? LOL

Going nuts with the mouse, maybe I have to have the unified dongle in because plugging in a USB from the Logitech mouse does nothing. When I go to preferences and try to install a bluetooth mouse, it eventually shows the name but won't actually install it. I can't find the Logitech dongle, so I ordered a new one from Amazon. I also have a spare Logitech older MS-3000 wireless keyboard and mouse that I could try but the big problem seems to be drivers for Mojave, on Logitech's web page the oldest driver is 10.15.X. I really hate the Apple 1152 mouse I have. LOL

 

[bladerunner88]

Hey Mike what you need to to do is make sure your booted into the OS you want, then go to Systems Preferences under the  Menu and select Startup Disk and you'll see icons representing your 2 patrons select the one you want to startup in. Also Yeah in order to select manually you would restart holding down the Option Key.
But not needed if you've already made your choice in Startup Disk