The installer is downloaded and installed in the /Applications folder. How to Download the macOS Catalina Installer: The installer is available from Apple as a developer’s beta or a public beta, or in its final released form from the Mac App Store (macOS High Sierra and earlier) or the Software Update preference pane (macOS Mojave and later). You can use the Migration Assistant app to restore your documents and data.

Found in some recent Macs, this controller adds an additional security layer that, in its default configuration, prevents your Mac from booting from any external source. T2-equipped Macs: Booting from an external drive, including USB flash drives, requires an additional step if your Mac is equipped with a T2 security chip. You can use a number of different cloning apps, including:Īny of the above apps can create a clone of your startup drive.ĪPFS: The drive you’re targeting for the installation of macOS Catalina will be converted from its current formatting to the newer APFS (APple File System). I usually recommend having a current Time Machine backup as well as a current clone of the startup drive. Always plan on the worst-case event, and have a recovery plan to get you back up and running in the fastest time. Notes and Informationīackup: Let’s start with the obvious: Before you embark on any upgrade to your Mac, make sure you have one or more current backups available. Once you finish the install, jump ahead to Post Install: Configure macOS Catalina. You should read through the Notes and Information sections, and then pick which of the two types of clean installs you with to perform.

I’ve organized this guide into four sections: If it does have an OS on it, you’ll need to erase the drive first to ensure a clean installation. The second method has fewer steps, and erasing the target drive is optional, as long as it doesn’t contain any version of the Mac OS. The two methods are similar, though the first, installing on a startup drive, requires a number of extra steps including creating a bootable installer and erasing all data from the startup drive. We’re going to look at two types of clean installs: installing on the current startup drive and installing on a drive that isn’t the startup and doesn’t contain an operating system. So, starting from scratch may be the better choice. You can restore your user data to a clean install but if you’re going to the effort of wiping your startup drive, you’ve probably been having some type of issue that could come back if you restore from the old data. It’s like the day you turned on your Mac for the first time. The downside to a clean install is that not only is the system a new, fresh copy, but your user data is new as well or a better way to put it: all your data is gone, erased.

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