This did not solve the problem. When updates are available, the App Store item under the Apple Menu on the Menu Bar usually shows x number of updates available. It did not show the OS update as being available. The only reason I knew about it was I saw that it was required before updating the ProApps. After updating the OS and rebooting, neither the App Store menu item or the App Store itself showed the ProApp updates. (I did not try downloading or updating the ProApps prior to updating the OS). I went to the MyAccount portion of the AppStore and opened the Purchased page. It showed my currently installed Apps and each had an "Open" button on them, rather than an "Update" button. On that same page, I found that if I clicked on the graphic for the program itself and not the 'open' button I was taken to another page which showed info for the app and had an 'update' button in the top-right part of the page. The program that I had previously received a notice that an update was available for (MediaInfo) also had the problem with not showing up in the AppStore after the OS update. I had to use the same procedure of going to the Purchased page in the AppStore to download it.
I was finally able to find a workaround to enable downloading the ProApps, but it was far from intuitive.
