An update to the Microsoft Outlook 2016 application released in April 2018 has caused it to repeatedly prompt certain users for their username and password information.  In some cases, this will occur during an already-configured profile that was previously connecting the Exchange mailbox without issue.  In other cases, this will occur during the configuration of a new profile, with the username/password dialog attempting to connect to a third-party server.  This article provides the recommended workaround steps to correct this username/password issue.

Prior to making any changes, we recommend testing the affected user's credentials by logging into the web OWA interface at to ensure they are working correctly.  In some cases users had attempted to reset their passwords in response to the username/password prompt, resulting in an incorrect password on the server.  Once the user has confirmed they are able to log into the web interface, proceed with the following steps.  If the user is experiencing the password prompt in a previously working profile, please use Step 1 first.  If the user is experiencing the issue while attempting to create a new Outlook profile, please skip Step 1 and proceed to Step 2.

Step 1: Forcing Outlook to re-authenticate

  1. Close Outlook. Allow enough time to ensure the Outlook process has closed completely (checking the Windows Task Manager to verify the Outlook.exe process is no longer running is recommended).
  2. Re-open Outlook.
  3. When prompted for credentials, press the X in the top-right corner to close the security dialogue box. Outlook will remain open.
  4. The Outlook status Bar, bottom most bar of Outlook, will contain a small yellow caution triangle alert or text stating "Password Required". Click the alert and enter the proper mailbox credentials.
  5. If the security dialog box appears, re-enter both the user's username (their full email address) and password.

In the event the above solution does not resolve this issue for the user, we recommend proceeding to the next step:

Step 2: Installing the Outlook 2016 Autodiscover Patch

  1. Download the Outlook 2016 Autodiscover Patch from the following support article:

    Outlook 2016 Autodiscover Patch

  2. Once downloaded, run the patch file.
  3. When prompted, confirm the addition of the patch information to Windows Registry.
  4. Reboot the computer.
  5. Once the reboot is complete, re-start Outlook.  Outlook may ask for the user's credentials one more time, but in most cases this is not necessary.  If a new Outlook profile is being configured, proceed with the new profile creation process normally.  The process for configuring a new Outlook 2016 profile can be found in the following support article:

    Outlook 2016 for Windows Full Access Connection