Some users are discovering that Outlook sends winmail.dat files attached to messages when sending to contacts in their address book. Only Outlook on Windows desktop (all versions) is affected; messages sent from Outlook on the web or the Outlook app do not have the rogue winmail.dat file.
How to resize images in Outlook on the web.
Outlook 2013 or Outlook 2016 users who are connecting to their Outlook.com account using Exchange ActiveSync (EAS) will need to remove the account from their profile and add it back using auto account setup, EAS accounts will stop working in the near future.
After an Outlook.com account is moved to the new Outlook.com server Outlook 2010 users will need to remove the Outlook Connector account from Outlook and add the email account back using auto account setup, but a number of users cannot get the account setup in Outlook 2010 as an Exchange account.
Custom Domains are once again available in Outlook.com.
How to change the display name for Outlook.com email accounts moved to the new server.
Users with POP3 or IMAP accounts who created Outlook.com accounts using their own email address, to sync just their calendar and contacts have noticed a problem after their account was migrated to the new server and opened in Outlook 2016: all replies use the Outlook.com account, not the account that downloaded the message.
Sharing Outlook.com Calendars with other family members
How to remove (the new) Outlook 2013 and 2016 Add-ins from Exchange online and Outlook.com accounts.
After outlook.com account is migrated to the new server, Outlook 2010, 2007, 2003 users need to remove the Outlook Connector account and add the account back to Outlook.
The big news for anyone who uses Outlook.com for email, or to sync calendar and contacts to smartphone: Outlook.com is moving to the Office 365 infrastructure in 2015.
Microsoft started moving Outlook.com users to the Office 365 interface earlier this week. Learn about the features and changes you can expect to see when your account is moved.