Custom Domains are once again available in Outlook.com.
Change Account Name in Outlook 2016
How to change the account name for Outlook.com and Exchange accounts in Outlook 2016 when the account name field is not editable.
Disable Outlook Add-ins (Apps)
How to remove (the new) Outlook 2013 and 2016 Add-ins from Exchange online and Outlook.com accounts.
Backspace doesn't work In Outlook on the web
An Office 365 user complained that he couldn't use backspace in Outlook on the web when he opened his account in Microsoft Edge. (Both Exchange online and Outlook.com after affected, although only a small subset of users of either service have this issue.) Users with problem can choose from one of two workarounds to fix
Sharing Outlook.com Calendars
Sharing Outlook.com Calendars with other family members
Add an Alias to an Outlook.com Account
How to create an Outlook.com alias to use to log into Outlook on the desktop when your Microsoft account uses a non-Microsoft email address.
Live Mail 2012 and Outlook.com
Live Mail will no longer sync calendar and contacts with Outlook.com after the account is migrated to the new server. You will be able to use it for email, using IMAP (preferred) or POP3.
Blocking domains in Outlook.com
How to block email from specific domains in Outlook.com using a rule.
ActiveSync Error 0x86000c1f
Error code: 0x86000c1f when attempting to Outlook.com accounts to Windows 10 Mail app or Windows Phone.
Setup POP in the new Outlook.com
After the Outlook.com accounts are moved to the new server, you'll be able to add the account to Outlook as an Exchange account or to any email client using POP3 or IMAP. But if you want to use POP, you'll need to enable it Outlook.com's Options.