First, I saw it happen on my friend’ss mac. Then I stumbled upon a few other incidents reported on mac forums. So I decided to write about it. One of the common cause of the issue is using different Appstore ID than which was used to install the current version. Solution is
- Either log out and log in from the same ID
- Try updating in Logout
- Put your mac in recovery mode and install latest OS by choosing reinstall MacOS
Take BACKUP