Your disk must be named “Untitled” and formatted with the “Mac OS Extended” option.
A USB thumb drive or external disk with at least twelve gigabytes of available storage.
A compatible Mac computer with macOS Catalina.
Prerequisitesīefore proceeding with the creation of your bootable installer for the macOS Big Sure beta or public beta, here’s a quick checklist of the things you’ll need: Nevertheless, it’s helpful to have it handy for troubleshooting purposes and when installing the macOS Big Sure beta or public beta on multiple Mac computers without having to download the installer each time. You don’t need a bootable installer if you want to upgrade the current macOS on your startup disk to the Big Sur beta or public beta on a single machine. You can easily use your USB installer as a startup disk from which you can boot your computer in order to install the Big Sur beta or public beta. Having a dedicated macOS Big Sur beta installer on a USB thumb drive is a great option for people who have multiple Macs that they wish to upgrade to the macOS Big Sur beta. 3.2) Changing Secure Boot settings Why do I need a bootable installer?