Running Catalina & Mojave on same computer

Howies121 wrote:

I'm running Catalina 10.15.7 but I have a business program that can only run on Mojave or less down to 10.7. Can I partition my drive so I can have access to either OS?

yes, you could do that. but from what I can tell, that option is fraught with potential problems. I too have a need for an older macOS intermittently. but I don't dual boot from my local drive. I keep the local drive up to date (currently Ventura) and I have Catalina on an external Samsung T7 SSD. and an added bonus of running each macOS on separate drives, i'l not likely to lose both macOS at the same time because of a drive failure.

yes, I looked at that. and it is of course possible to partition the local drive and dual boot from it. I didn't say it could not be done. but because I have seen issues here many times while trying it, IMHO it is a bad idea to do that.

Hi, I hope I can revive this thread with one more question: I am running Mojave on MacBook Air 2015, and want to keep Mojave because I need to continue using some legacy applications, but I'll probably need to get a new computer soon, and I understand running Mojave may be a problem.

So, When you say I could only run Mojave if the Mac is compatible, is this true also if I boot from an external drive, as you suggested earlier, or only if I work with partitioned internal drive?

Thanks for your help,

ruth gabrieli wrote:

When you say I could only run Mojave if the Mac is compatible, is this true also if I boot from an external drive, as you suggested earlier, or only if I work with partitioned internal drive?

Macs cannot run versions of macOS that are earlier than what came with the Mac when originally new. If you purchase a new Mac now it will be an Apple Silicon Mac (M2 or M3) and come with macOS Sonoma - it will not be able to run Mojave. No new Mac will be able to run Mojave regardless of whether it's on an internal or external drive.

Howies121 wrote:

I'm running Catalina 10.15.7 but I have a business program that can only run on Mojave or less down to 10.7. Can I partition my drive so I can have access to either OS?

So have you checked for an update to that business program that brings it up to date? And if that business program is no longer supported or updated then why are you still using it? It's not very prudent to be using outdated software to run a business on. Neither is outdated hardware. Too many security and privacy issues that may bite hard.

Coincidentally just read an almost identical question which I partcipated in - it was solved - last post page 2

Create partition on APFS internal disk to… - Apple Community

and I should have added, you will only be able to run Mojave if the Mac is actually compatible with Mojave.

you're welcome. :)

Thanks