As you know, I run a Mojave Developer Beta on a separate SSD hard drive. It works fine, but the problem with that is you have to boot into it each time and then back into the main Mac. So, I decided to install the regular Mojave Beta which just came out the other day into a Parallels Virtual Machine. I am sure you could do something similar with VMware Fusion or VirtualBox. Now, I do not need to reboot to use Mojave. Plus, I can use it along side work I am doing in my main machine running High Sierra. Here is what I did to install this I am sure there are other ways of doing it.
Parallels Mojave Install
If you are running a virtual app like Parallels, you can to this with any Mac OS. I think people install a Mac OS in a Virtual Machine to run older software or to do Beta testing like me. Here is how this all works in Parallels.
When you first open Parallels you can do all kinds of installs. I suppose if you had a Disk Image of Mojave you could use the middle choice in this menu to install it:
If you scroll through the choices in the bottom of the window, you will eventually come to an option to install your current version of macOS using its Recovery Partition. This is a totally cool feature. So, that tis what I did. When you choose installing with the Recovery Partition it downloads the OS and does an install into the Parallels Virtual Machine:
After it installs High Sierra, it boots into it. Then this is what you have to do. Obviously, you have to sign up for Apple’s Beta Program if you are not enrolled already. You will find a link that says “Enroll your Mac.” When you click on that you will be taken to a page that has a download link for the Public Beta Access Utility:
You download this little app to your High Sierra Desktop, double-click it and it will download and install Mojave over the top of High Sierra:
I know this seems a little convoluted, but it really is pretty easy, especially if you are already signed up for the Beta program. Then, you just have to download the Beta Installer Utility and go for it.
Needless to say, this is a bit involved. However, it is worth the time up front just to be able to access the Mojave Beta so easily. Now all I do is startup Parallels and click on the Mojave Virtual Machine and, I have Mojave running in a window on my Desktop. It is a little slower than a separate install, but so much more convenient.