This blank notification banner appeared out of nowhere, at the top-right corner, and won't go away even if I restart/shutdown the MacBook, kill Dock, Finder or Notification Center. It won't appear if I boot in Safe Mode though. If I have two desktops open by using Spaces, only the first one will have this on, but if I close it, the banner will move to the second one.
Has anyone experienced something like that? I'm on a 13" MacBook Pro running macOS Sierra version 10.12.5.
Best Answer
I just had the same Problem and disabled all Notifications with no result.
Then I tried stopping some apps and found that the "EthernetStatus Mini"-App was responsible for it.
EthernetStatus Mini running (Banner always appears when Starting EthernetStatus Mini)
EthernetStatus Mini stopped