App store quit unexpectedly
MacBook Pro (Retina, Mid 2012), macOS Sierra (10.12.5)
Manually download and install this combo update. It will hopefully correct what is going on.
Download macOS Sierra 10.12.5 Combo Update
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
App store quit unexpectedly