macOS Catalina dmg file download for old macbook pro

Although macOS Catalina is no longer the newest macOS version, many users still need the macOS Catalina DMG file for installing macOS on older Macs, creating a bootable USB, or running Catalina in a virtual machine. In 2026, Apple does not always provide a direct DMG download page, but there are still several reliable ways to obtain it safely.

Apple still hosts the Catalina installer through its support website, though it usually downloads as an installer app instead of a DMG file.

Steps for mac catalina dmg download

1. Open the Apple Catalina download page.
2. Click Download macOS Catalina.
3. The App Store will open automatically.
4. Click Get to download the installer.
5. After downloading, the installer appears in the Applications folder.
6. You can convert the installer into a DMG file using Terminal if needed.

Pros

Official Apple source

Safe and verified installer

No third-party tools required

Cons

Usually downloads as .app, not DMG

Requires converting the installer manually