What practical options exist for running 32-bit applications on Catalina (macOS 10.15)? After I had a disturbing discussion with an Apple engineer I realized that Catalina is heading at us like a freight train right now - and not necessarily in a good way, but acceptation is going to be mandatory by Apple. In my case and revelation, I've been having some troubles with macOS over the last several months with performance on Mojave and it appears that these issues have been resolved in Catalina, but we're not going to see a "back port" of these fixes in Mojave. This is a double edged sword for some of us who need to run 32-bit programs still!

So this leads me to the question: what realistic options are we looking at for being able to run 32-bit apps when we must to step into Catalina?

Thus far the only practical solution that's come to my mind is using Mojave or High Sierra in Parallels via Coherence or another VM. Some projects like Darling (via Linux; imagine Wine for macOS apps instead) are just not yet quite mature enough to be viable. Are there other options that will facilitate running 32-bit apps that we just can't run without when Catalina becomes a proverbial "necessary evil?"
I guess it depends on what you mean by realistic options?

In summary though, the three best options are:


use a virtual machine (as you've already mentioned)
use a second boot disk (e.g. an external drive, another partition on your internal drive, etc) that has another version of macOS installed and boot from that as required
have a second Mac with another version of macOS installed. Depending on the Mac model, with this option you could also use the Mac in Target Disk Mode to boot your primary Mac if/when required.


Which ones of the above are the most realistic will depend on your individual circumstances.