Configuring preferences and options in Outlook.com
Hi CarolineASD,
We apologize for the delayed response to your concern as we are now having a high volume of support request from customers. We appreciate your effort in sharing your thoughts to our feedback page.
Rest assured that Microsoft is reviewing what customer's have posted there to consider the features that should be added in the new Outlook interface for product development. Currently, we don't have an option to turn off automatic log in to Messenger, you can just turn your profile as "Invisible" while checking your emails.
Your patience to this matter is very much appreciated.
Thank you.