itunes 12.6.2
It keeps saying "an error has occurred" “iTunes” could not be verified.(311).
MacBook Air, macOS Sierra (10.12.6)
You can manually download and install iTunes from here;
ASC - Late 2012 Mac mini, macOS 10.12.5; Watch, 38 mm silver AL, watchOS 3.2.2; iPad Air 2 & iPhone 7+, iOS 10.3.2; TV 4th Gen, tvOS 10.2.1; Airport Express