Microsoft apps not opening, Ms excel not working, MS word not working
Sometimes when you are trying open MS APPS in Samsung mobiles but it doesn't open. So there is a very simple solution for such problem.
SOLUTION
Go to settings - > Application Manager - > scroll towards right and go to disabled apps - > enable galaxy apps.
Or
Go to settings - > Application Manager - > scroll towards right and go to ALL - > open options - select reset app preferences