Once you've downloaded the macOS Catalina 10.15.7 .dmg file, you can install it on your Mac using the following steps:
The following Mac models are compatible with macOS Catalina: Early 2015 or newer MacBook Air: Mid 2012 or newer MacBook Pro: Mid 2012 or newer Mac mini: Late 2012 or newer iMac: Late 2012 or newer iMac Pro: All models (2017) Mac Pro: Late 2013 or newer download macos catalina 10157 dmg file install
Click . Once finished, the file named Install macOS Catalina.app will be placed directly into your /Applications folder. Method 2: Extracting a DMG via Terminal (Advanced) Once you've downloaded the macOS Catalina 10
🛑 This command erases everything on the target USB drive. Catalina is 64-bit only
Catalina is 64-bit only. 32-bit apps will not run. Check your apps under System Report > Software > Legacy Software .
A bootable external drive is highly recommended for clean installations, troubleshooting, or deploying Catalina across multiple machines without re-downloading the asset.
If you are coming from an older OS (like Mojave), Catalina also introduced: How to download and install macOS - Apple Support