If it doesn't open, go to your Applications folder and double-click "Install macOS Catalina."
Your Mac will restart automatically. Do not turn off the Mac during this process, which may take up to an hour or more. Phase 4: Post-Installation & Finalization
The upgrade process (typical path)
If you are using a MacBook, ensure it is plugged into power.
Before you do anything, confirm your Mac supports Catalina. Catalina drops support for many 2010-2012 Macs that ran High Sierra. how to update macos high sierra 10136 to 1015
Because of the version gap, you cannot simply click "Update" in System Preferences. You need the full installer. Open the App Store on your Mac. Search for "macOS Catalina".
Verify that your Mac model matches or exceeds the following requirements: Early 2015 or newer MacBook Air: Mid 2012 or newer MacBook Pro: Mid 2012 or newer Mac mini: Late 2012 or newer iMac: Late 2012 or newer iMac Pro: 2017 or newer Mac Pro: Late 2013 or newer If it doesn't open, go to your Applications
Your Mac will restart, show a black screen with an Apple logo and progress bar, then restart again (sometimes twice). This is normal.