mac oS catalina
You’re ready to take the plunge, but what are the pitfalls?
Upgrading macOS is simple: download the new version from the Mac App Store and install it – like updating an app, but with a couple more automatic restarts. It won’t usually take more than an hour. For the first time, macOS Catalina will create a separate partition for itself as a safeguard against accidental changes. But all your apps and files will still be where you expect, and everything should work the same as before. Well, almost everything, as we discuss below and opposite.
You could erase your startup drive and install the new macOS from scratch. There’s a popular myth that this will somehow reinvigorate your system, but these days if you use your Mac in fairly normal ways, it’ll keep itself running fairly efficiently, as long as your startup drive isn’t completely full (see page 22). A clean install is a hassle, involving a USB drive and Terminal commands, and unlikely to give much benefit. Afterwards you’d want to restore your apps and files, but if you put everything back you won’t
have cleaned anything up, and if you don’t you’ll misplace settings, plug-ins and data. Is it worth it? No.
Alternative install
One option is to install macOS Catalina on a different, empty drive. This makes sense if, for example, your Mac has an internal hard drive but you want to get a speed boost by adding a Thunderbolt 3 SSD. The catch is that all your personal files and settings will still be in your user folder on your startup drive, while macOS now references the new empty folders. You’ll need to drag files across. Alternatively, restore (clone) your startup drive to the new drive (see page 23), then do the Catalina upgrade on that. If the new drive is smaller, you may first need to copy a bunch of big files to a third drive, then delete them. Afterwards, erase your internal drive to remove the old copy of macOS, then use it to store whatever you choose.