Mac app store has update icon but has no update
Running OS X High Sierra version 10.13.2. Have done all updates possible but can't get rid of the App Store icon red 1 that indicates 1 update is available in the Dock. I've deleted the App Store cache, tossed out the icon, turned off Spotlight and other things to no avail. It keeps telling me an update to Mac OS X El Capitan is Available and I even downloaded it once in the hope that would get rid of it but it just won't go away. I like my Mac to work right not annoy the *@%#$ out of me because of this stupid little icon problem. The Mac OS has had this problem since the introduction of the App Store. One would think this would have been worked out by now.
Mac Pro, macOS High Sierra (10.13), MacBook Pro, iPad