Optional versions of OS?

[vindunn]

Hi
I have Mojave on my imac (27-inch, Late 2013), but there are some apps and peripherals I can’t use any more since I upgraded. Can I put an earlier version of Mac OS (eg Sierra or Yosemite) on an external drive and have the option of booting off either the main disc or the external when I want to run the older apps and peripherals?

Can I even get installer software for an older OS? Apple doesn’t seem to offer much. I have older versions of everything backed up on Time Machine, but I’m afraid to restore using TimeMachine since I think I would lose everything since the upgrade.

Clearly I need help here, and would really appreciate any advice. Thanks,

Vin

 

[Lufbrarunner]

Yes this is possible, Instructions.
I have external drives set up with El Capitan, Sierra and Windows 10. I just have to hold the 'Option' key when booting to give me the opportunity to select which OS I want to boot to.

 

[vindunn]

Yes this is possible, Instructions.
I have external drives set up with El Capitan, Sierra and Windows 10. I just have to hold the 'Option' key when booting to give me the opportunity to select which OS I want to boot to.

Many thanks for the quick and helpful reply.
Vin

 

[vindunn]

Hi again. New problem: I bought an external drive, intending to use it as my second boot drive, following the kind advice above. The trouble is getting installer software for Sierra or any of the older OSs that would run the apps I lost when I upgraded to Mojave. I downloaded the links that I've been able to find on Apple's website (impossible on the App Store for anything that old) but they give the message when I try to install with them that the drive already has to have a Mac OS running. So these installers are really upgrades, I guess. Part of the problem I think is that I don't have the actual installer software for my iMac. It must have come pre-installed, so no disc copy. According to docs, the iMac would have come with Mountain Lion—but no disc!
I thought maybe I could use TimeMachine to restore pre-upgrade-to-Mojave an older backup, but when I tried, I couldn't select a specific date's back up. It only gave me the option of installing the whole year's worth of backups as a single disc.
Is there some site where I can buy or beg an installer that doesn't require that there already be a Mac OS running on the destination disc? I'm starting low with Sierra, but I was probably up to at least Yosemite when I upgraded. It needs to be able to work with 32-bit apps and my Canon scanner.
Why is Apple so terrible about giving access to archaic software? Are they that mercenary?