Focused Inbox disappears when you switch folders in Outlook
Symptoms
You set up a Microsoft 365 account in Microsoft Outlook. When you switch from the Inbox to other folders, such as the Sent Items folder, and then you return to Inbox, the Focused Inbox option disappears. Additionally, the option on the View tab to turn on or off the Focused Inbox also disappears.
Cause
This issue occurs because the Autodiscover process that's used by Outlook did not retrieve the XML from Microsoft 365, and received an unexpected result from a third-party web server that uses IMAP settings from either https://<Rootdomain>/autodiscover/autodiscover.xml or https://autodiscover.<Rootdomain>/autodiscover/autodiscover.xml.
Typically in this situation, the lookup fails and Outlook eventually performs an Autodiscover lookup against https://outlook.office365/AutoDiscover/AutoDiscover.xml. However, because Outlook receives a successful Autodiscover response that has IMAP settings, it marks the account as a non-Microsoft 365 account, and then stores the Autodiscover URL as the Last Known Good URL in the profile.
To verify you're experiencing this issue, use Microsoft Remote Connectivity Analyzer to test the Outlook Autodiscover process, and then search the text in the test results for the "IMAP" text string. Typically, "IMAP" doesn't appear in the test results unless a third-party web server is responding to Autodiscover requests.
For more information about the Autodiscover service, see How the Autodiscover service works.
Resolution
Contact your web service provider or the web hosting provider of your domain website to make sure that the web server isn't responding to the following Autodiscover requests:
https://<Rootdomain>/autodiscover/autodiscover.xmlhttps://autodiscover.<Rootdomain>/autodiscover/autodiscover.xml.
Workaround
Important
Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
To work around this issue, exclude the Last Known Good URL by setting the ExcludeLastKnownGoodURL registry key as follows.
| Type | Value |
|---|---|
| Registry subkey | HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Outlook\AutoDiscover |
| Value Name | ExcludeLastKnownGoodURL |
| Value Type | REG_DWORD |
| Value Data | 1 |
For more information about how to set this registry key, see Unexpected Autodiscover behavior.
Important
Because excluding the Last Known Good URL isn't a long-term solution for this issue, Microsoft don't recommend it. This workaround is provided as immediate relief for the issue. As soon as the web service provider or web hosting provider fixes the issue, this Outlook registry key must be removed.