Step 2: Create a bootable drive of macOS Catalinaīefore you downgrade your Mac and erase Big Sur from your computer, download macOS Catalina from the Mac App Store. If you don't save these important files somewhere off of your computer you will lose them. Use an external hard drive or a cloud-based program like DropBox, OneDrive, or iCloud. Erasing a hard drive means erasing everything. You also won't just revert back to the previous macOS with all of the files and folders exactly where you left them. That means any files, programs, or documents you've been working on will also be erased if you don't back them up first. This process to downgrade your Mac will erase macOS Big Sur from your hard drive entirely. Tick the box to Allow booting from external media. This will put your Mac into Recovery Mode. Hold down Command+R right when you see the Apple Logo.
Make sure you know the correct password to access the Startup Security Utility before you begin. This is different from your administrative password and your Apple ID. Note: You'll need the firmware password you used to enable the Startup Security Utility. VPN Deals: Lifetime license for $16, monthly plans at $1 & more
