Press . The installer will download to your Applications folder. 3. Apple Support Combo Updates (DMG Format)

Practical Approaches to Obtain Catalina

If your goal is to create a bootable USB, you do not need a DMG file. After downloading the installer app, you can use the official createinstallmedia command in Terminal as detailed on Apple Support Terminal steps to convert that installer app into a DMG file? How to download and install macOS - Apple Support

command in Terminal to write the installer data onto this newly created blank DMG volume. Support and Compatibility macOS Catalina dmg file download for old macbook pro

Apple typically provides these installers via the . You can use the link below to open the specific page in your App Store: Download macOS Catalina from the Mac App Store Creating a DMG or Bootable Installer