Software & Apps MS Office How to Set the Default Account in Outlook Specify the address Outlook uses for new outgoing messages By Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated February 03, 2020 MS Office Outlook Word Excel Powerpoint Tweet Share Email When you reply to an email message, Outlook sends the reply using the email account that received the original message. If none of your email addresses appears in the original message, Outlook uses the default account to compose a reply. The default account is also used when you compose a new message. Instructions in this article apply to Outlook 2019, Outlook 2016, Outlook 2013, Outlook 2010, Outlook for Office 365, and Outlook for Mac. How to Set the Default Account in Outlook To set the default email account to the account you prefer to use: Go to the File tab. Select Info. Select Account Settings > Account Settings. Highlight the account you want to be the default. Select Set as Default. Select Close. Set the Default Account in Outlook for Mac To set the default account in Outlook 2016 for Mac or Office 365 on a Mac: Go to the Tools menu and select Accounts. Select the account you want to make the default account. The current default account appears at the top of the list. In the lower-left corner, select the cog icon and choose Set as Default. To send a message from an account other than the default account, select the account under Inbox. Any email you send will be from that account. When you are finished, select the default account under Inbox again.