I’ve tried a few times now but I get a message ‘you need to update to a later os’ when I try to boot up from the external.

Download MacOS Mojave from MacOS catalina. When done, keep the downloaded file in an external drive in order to use it later for the MacOS installation.

Erase macOS Catalina on Your Mac. The macOS Mojave is till now having more user then the latest operating system, which is macOS Catalina. Part 3: Time to Create Bootable Drive [macOS Mojave Bootable Drive] Next step is to create Bootable Drive to install the macOS Mojave on a separate partition.

Step 6: Install MacOS Catalina on PC or Laptop.

On the 10th of December 2019, Catalina 10.15.2 (19C57) was released, and enthusiasts all over the world have started to enjoy the many benefits it has to offer. Therefore, now I will guide you on How to install MacOS Catalina on PC or Laptop with External Drive. An external drive that you can use as an installer for macOS Catalina is a handy thing to have.

If the installer opens after downloading, quit it without continuing installation.

Once you’ve booted from your Mojave Installer drive use Disk Utility to erase the entire internal drive then install Mojave. Now, everything is ready plus your USB drive is ready too for installation. Consider Installing macOS Catalina on an External Hard Drive. macOS Catalina, macOS Mojave, or macOS High Sierra Installers for each of these macOS versions download directly to your Applications folder as an app named Install macOS Catalina, Install macOS Mojave, or Install macOS High Sierra. Step #4: Make sure Install macOS Mojave file is there is Applications folder. To use that drive to boot a Mac with a T2 security chip you must allow external booting from the Security Utility on the Recovery partition. At this stage, you can remove your USB 3.0 8GB Flash drive; After installation is done, the system will reboot and again you need to press boot options key to choose your external drive as boot drive where you just installed macOS Mojave Any ideas anyone? If you own a Dell or any other brand laptop powered by 7 th gen processors, this guide is for you.

As soon as system restarts, start pressing the boot options key usually F12 and choose your external drive from the option and press ‘Enter’ To use that drive to boot a Mac with a T2 security chip you must allow external booting from the Security Utility on the Recovery partition. Now to install the beta or alternative version of the Mac operating system on your external drive. To delete macOS Catalina, simply follow these steps below carefully.