# Create a blank image
hdiutil create -o /tmp/Catalina -size 8500m -volname Catalina -layout SPUD -fs HFS+J
# Mount and restore
hdiutil attach /tmp/Catalina.dmg -noverify -mountpoint /Volumes/Catalina
sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/Catalina --nointeraction
# Convert to ISO
hdiutil convert /tmp/Catalina.dmg -format UDTO -o ~/Desktop/Catalina.cdr
mv ~/Desktop/Catalina.cdr ~/Desktop/Catalina.iso
Note: This ISO is for personal virtualization only, not distribution.
Some users need Catalina to run 32-bit applications (the last macOS to support them) or maintain compatibility with legacy hardware/software. Version 10.15.7 was the final, most stable release of Catalina. macos catalina 10157 iso download new
Since VMs require ISO files, the community has developed safe methods to convert Apple’s official installer into a bootable ISO. # Create a blank image hdiutil create -o