Home Forums Mac Software Mac Operating Systems OS on external HD

OS 10.14.6

I have Mojave on my computer. I would like to install OS 10.15 on an external HD. The reason is because if I don't like it, I can just erase it.

Can this be done, if so, how?

jaybass

Easy!

1. Follow the link at https://support.apple.com/en-us/HT211683 (How to download macOS - Apple Support) to download the macOS Catalina installer from the App Store by clicking on "Get." The page looks like it's giving you the 10.15.7 update, but you get the full installer.
2. Connect your external to your iMac.
3. Launch the installer.
4. Select your external when asked on which volume you want to install.
5. Let 'er rip!

If you need any help formatting your drive, post back.

artie,

I have installed Catalina on an external HD. Can't say I'm too impressed with it. We shall see.

Thanks,

jayass

It's been 2+ years since I've dealt with Catalina, and I haven't got even the foggiest recollection of how I felt about it.

I feel that macOS has become so stable that rather than look for impetus to upgrade, I do it simply to smooth out the learning curve. I'd skip an upgrade only if I tried it and hated it.

artie,

After taking a second look at catalina, I think I'll pass. I've come to like Mojave.

jaybass

I certainly can't fault you for staying within your comfort zone, but I will say that although I skipped Tiger with minimal down-the-road shell-shock, later on, when I skipped Lion, Mountain Lion, Mavericks, and Yosemite in succession, the learning curve was awfully daunting.

Another point to consider, as you fall farther and farther behind the OS development curve, there is less an less support. App developers are focused on the current version as are the majority of users and troubleshooters no longer have exemplars to work from and memories become vague. That leaves you more and more on our own.