Once the download completes, the "Install macOS Catalina" app will appear in your Applications folder. 2. Creating the DMG from the Installer
Visit the official macOS Catalina page on the Mac App Store. download macos catalina dmg
Whether you're looking to revive an older Mac, set up a virtual machine, or create a bootable installer, obtaining a clean is the first essential step. Since Apple has moved to newer versions like Sonoma and Sequoia, finding the official Catalina installer can be a bit of a treasure hunt. Once the download completes, the "Install macOS Catalina"
This method is preferred because it uses the official, cryptographically signed Apple installer. Third-party pre-made DMGs found online may be modified, outdated, or contain malware. Whether you're looking to revive an older Mac,
By default, Apple downloads an .app file, not a .dmg . If you specifically need a DMG file for a virtual machine (like VMware or VirtualBox) or a bootable USB, you can use a terminal command or a third-party tool like DiskMaker X or the built-in createinstallmedia command to package it.
As of late 2024/early 2025 context, macOS Catalina is considered "Obsolete" or "Vintage" by Apple's service definitions. This means:
Strictly speaking, Apple does not provide a raw .dmg file of the full macOS Catalina installer. Instead, they provide an Install macOS Catalina.app inside a .dmg (or as an app downloaded directly from System Settings).