Hide the Giant MacOS Sierra Update Banner on the Mac App Store With One Click
If you haven’t updated to macOS Sierra , you’re probably quite annoyed by the giant banner that appears in the App Store updates tab. Fortunately, OS X Daily indicates that you can get rid of this.
Open the App Store as usual, then click the Updates tab. If you don’t use Sierra, you will probably see a huge banner asking for an update. Right-click this banner and select Hide Update. That’s it, the big Sierra banner will disappear.
How to hide the macOS Sierra update banner in the Mac App Store | OS X Daily