The installer will delete itself when you install the operating system, but it can be re-downloaded if necessary.

The macOS 10.15 Catalina installer from the Mac App Store (in High Sierra or older macOS versions) or the Software Update preference pane in Mojave.A USB 3.0 drive will make things significantly faster, but an older USB 2.0 drive will work in a pinch 8GB drives worked for Mojave and older versions of macOS, but the Catalina installer is just a little too large to fit. A 16GB or larger USB flash drive or a 16GB or larger partition on some other kind of external drive.We've created a USB stick from both Mojave and Catalina, but your experience with other versions may vary.

A Mac that you have administrator access to.Luckily, it's not hard to make one-either with a handy graphical user interface or some light Terminal use. Further Reading macOS 10.15 Catalina: The Ars Technica reviewĪpple hasn’t shipped operating systems on physical media in a full decade, but there are still good reasons to want a reliable old USB stick for macOS Catalina.

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