Sierra 10.12.1 Upgrade

Your late 2011 mac can only upgrade as far as MacOS High Sierra (10.13.6)

Please use Safari to access the following link do not use Firefox

How to upgrade to macOS High Sierra - Apple Support

Before upgrading make a full back up of your Mac.

Check that third party apps you use have updates available for the new OS.

https://roaringapps.com

Check that your printers/ scanners etc have updated drivers and software available for the new OS.

Connect your mac to your router via cable rather than rely on WiFi.

Do not use your mac while it is downloading

and do not use any other devices that share the same internet connection.

If the App Store says Open then it is detecting a previous download of the install app

go to the Applications folder locate Install macOS High Sierra.app.

Move it to the Trash, empty the Trash.

Restart, click on the link again, the App Store should say ‘Get' or 'Download'.

On your version of macOS, the way to get the free update is through the App Store. Launch that and do a search for Catalina in the search field in upper left corner. It is a free upgrade.

Here is a support article with more information: https://www.apple.com/in/macos/how-to-upgrade/

Please be sure to make a full backup of your current hard drive prior to any major updates. (Either with Time Machine, or a different service of your choosing)

See Step 2 in these instructions for how to backup your Mac: https://support.apple.com/en-us/HT201475