Once you have the legitimate Install macOS Catalina.app , you can easily create your own DMG for backup or transfer it to a USB via the createinstallmedia method. This ensures you have a clean, bootable, malware-free copy of one of Apple’s most transitional operating systems.
sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume (Replace "MyVolume" with your USB drive's name) Installation via Recovery Mode Download Macos Catalina 10.15.7 Dmg File
: For Macs running any version of Catalina (10.15.x). Download it from Apple Support (106405) Official Ways to Get the Full Installer Once you have the legitimate Install macOS Catalina
Assumes you have “Install macOS Catalina.app” in /Applications. Download it from Apple Support (106405) Official Ways
The safest way to get macOS Catalina is through official Apple channels to ensure the installer is untampered and secure.
hdiutil attach ~/Desktop/macOS_Catalina_10.15.7.dmg -readwrite -mountpoint /Volumes/Catalina_Base Use code with caution.
hdiutil attach /tmp/Catalina.dmg -noverify -mountpoint /Volumes/Catalina Use code with caution.