This is the error from the log in admin menu
Resource string (admin.configuration.plugins.applychanges.progress) is not found. Language ID = 1
Resource string (admin.configuration.plugins.discardchanges.progress) is not found. Language ID = 1
However I saw this error being fixed by nopcommerce some months back in another post and since I downloaded 4.2 recently i'm not sure why it's still there.