Open Terminal and paste the following: sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/Catalina

If the App Store link fails, you can use the Terminal to fetch the installer directly from Apple's servers: Open .

Are you looking to or perform a clean install on an older MacBook?

Here is everything you need to know about downloading and installing macOS Catalina 10.15.7. Why 10.15.7?

Enter your admin password and wait for the process to reach 100%. macOS Catalina System Requirements

Once you have the installer file, you’ll likely want to put it on a USB drive (16GB minimum) to perform a clean install.

The safest way to get the installer is directly from Apple. However, Catalina no longer shows up in basic App Store searches on newer Macs. Download macOS Catalina via Mac App Store

Open Disk Utility , select your USB, and format it as Mac OS Extended (Journaled) with a GUID Partition Map . Name the drive "Catalina".

If you are downloading a DMG from a third-party site because you are on a Windows PC (for a Hackintosh or VM), always verify the SHA-1 hash of the file to ensure it hasn't been tampered with.