Can I create a separate Catalina partition on an external disk and just boot into it when needed?
I need to stay on Mojave for a time but would like to try out some Catalina features == is that possible by either creating a partition on my iMac hard drive [it's 1T but probably not enough room left to do a decent test] or having an external internal drive attached to the iMac and just booting into it when needed? How do I do that if I don't want to/can't overwrite my Mojave OS???
iMac 27" 5K, macOS 10.14