Read Your Emails When Your Pc is not connected With Internet.Yes In Windows 8 this Feature is Available With Mail App .Its Pre install with every Genuine Windows 8 or 8.1.I Know Most Of People Is Used This App Like Me 🙂 but I Don’t That it store mails in offline mode.Today i am Surfing On Internet and My Wifi Router Is Turn Off Because OF Some Reason.And Then i See My mail Still Shows My All mails To Me Then I Thing Its Due To Cache Memory. For Check I Restart My Laptop And Clear All Cache And Then Check The Mail And I Shocked That It Still Showing all Mail without internet Connection.
Mail App store about of 50 previous Emails In Your PC Memory And Even Internet Is Connected Or Not It Will Show You The Email.If You Are Connected To Internet The It Update The Mail List Otherwise Not.You Can Choose Your update Frequency like Hourly,Weekly and Update when a new email is receive.
Here is A Video In Which You See Demo