Catalina install
My Catalina won’t install? I get a message saying that I need be running Mac OS Catalina 10.15 or later to install onto this volume
iMac 27", macOS 10.14
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You have downloaded an updater, not the full installer. See How to upgrade to macOS Catalina. To avoid possible problems with an installation, I recommend doing the following:
Repair the Drive for El Capitan or Later
- Restart the computer. Immediately, at or before the chime, hold down the Command and R keys until the Apple logo and progress bar appear. Wait until the Utility Menu appears.
- Select Disk Utility and press the Continue button.
- Then select the indented (usually, Macintosh HD) volume entry from the side list.
- Click on the First Aid button in the toolbar and wait for the Done button to activate. Click on it, then quit Disk Utility.
- Select Restart from the Apple menu.
Backup your files to an external drive. I suggest making a bootable clone in case a catastrophic problem occurs.