Have you noticed when you sign in to your Windows 8 using your Microsoft Account, apps like Messaging, Mail, People, Calendar and so on will automatically sign you in. This is for your convenience so that you do not have to sign in to each app individually.
Disable Auto Sign In Of Messaging App in Windows 8
While many find it useful, some may not want the Messaging app to sign in automatically. To disable the auto-signing of the Messaging app, open it and press
Win+I to open the
Settings.
Click on
Option.
You will see an option to
Disable or Enable All messaging services viz. Send or Receive messages. Move the slider from On to
Off.
That is all!