It is important that you back up your Mac before you do anything.
Please try the tips belove if you are unable to update your computer: Sometimes, you may see an error message saying “The macOS installation couldn’t be completed” or “macOS could not be installed on your computer”. By stalled, we mean that macOS updates won’t download and install successfully.
Some Mac users, unfortunately, have been and continue to be affected by various macOS software update issues where they may experience a stalled macOS update. More specifically, the focus of this article is on what you can do to when your Mac won’t update to the latest version of macOS. This article explains how you can fix the software update problem.
