Yesterday my mail app and calendar, and several other apps that I don't use, greyed out. When I click on them I get told that "This app can't open" and it unhelpfully suggests I go to the App store to find out more about mail. fixes suggested are mainly to uninstall the app and then reinstall via the store but I am unable to uninstall the app. Even when I think I have done it, when I go into the store it tells me I already have the mail app!!
I have run out of ideas as to how to fix this. Can anyone help?