I've had performance issues running 10.11.4 Beta and I've decided to pull my iMac off the beta track. I've restored back to 10.11.3 and unenrolled from the beta program. However, when I restore my computer post "downgrade", an upgrade to the 10.11.4 beta is sitting in my Appstore upgrade tab. I've gone to the App Store preferences pane, but there is no "Your computer is set to receive beta software updates" button to change. Nor is there an "Install OS X 10.11.4" icon in Launcher or the Application folder. How can I get rid of this upgrade? Right now, it will install as soon as I restart my machine and I'll have to go through this whole thing all over again. Is there somewhere else, hidden or otherwise, where this update is that I can delete it? This is really, really frustrating!