How to Create macOS Catalina ISO File



Please note these steps need to be performed on a Apple Mac System to generate an iso.

Steps:

1) Download macOS Catalina From App Store or Apple download

2) Please note once you download it will be in dmg format.

3) Open Terminal in MAC. from the top-right corner open up Spotlight. Type in Terminal and hit Enter.

4) Mount it to your macOS

hdiutil attach /tmp/Catalina.dmg -noverify -mountpoint /Volumes/Catalina

5) Create macOS Catalina Installer

sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/Catalina --nointeraction

6) Unmount Catalina Disk

hdiutil detach /volumes/Install\ macOS\ Catalina

7) Convert the DMG file to an ISO file

hdiutil convert /tmp/Catalina.dmg -format UDTO -o ~/Desktop/Catalina.cdr

8) Rename and Move to Desktop

mv ~/Desktop/Catalina.cdr ~/Desktop/Catalina.iso


Now we can use this iso on any system and install on virtual machines.