Earlier today, Apple released a new version of Sierra, OS 10.12.5. Here are its features: http://osxdaily.com/2017/05/15/macos-sierra-10-12-5-update-released/ In any event, I "went" to the App Store to see if I can download the entire OS 10.12.5 OS (like I have always been able to), but all it will allow me to do is "Open" it so that it can update my OS 10.12.4 "system". While that might be convenient, I never do OS updates that way. I either will download the full, new version, or the Combo Updater. It looks like in this case, I'll have to wait for the Combo Updater (should be available no later than tomorrow). I was wondering if anyone can explain why this would be the case with this update. Seems rather strange.