Shared mailbox emails are not updating automatically in Outlook

For new Outlook for Windows, this behavior can be expected when the shared mailbox was added by automapping. Incoming email in the Inbox of an automapped shared mailbox is not automatically synchronized. It updates when Sync is selected in the View section of the ribbon or when the folder is selected.

If automatic sync and notifications are required, add the shared mailbox as an account instead of relying on automapping.

If this is actually classic Outlook rather than new Outlook, there is also a known issue where shared mailboxes stop updating automatically and Outlook can show “Updating this folder”. Since removing and re-adding the mailbox and creating a new profile were already tried, the remaining documented checks are:

1. Check the Sync Issues folder of the primary Exchange account for synchronization log errors.
2. If the profile is in the known broken state, either:
   • create a new Outlook profile, or
   • remove the profile corruption by deleting the 0102663e registry key under the affected Outlook profile.

Warning: Registry editing is risky and can cause serious problems if done incorrectly. Back up the registry first before making changes.

Registry path: Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Profiles

Then:

• select the affected Outlook profile
• use Edit > Find and search for 0102663e
• locate the key where the parent key is just above GroupStore
• delete 0102663e
• restart Outlook and verify the shared mailbox updates

So the key distinction is:

• New Outlook: automapped shared mailboxes do not auto-sync Inbox; add the shared mailbox as an account for automatic sync.
• Classic Outlook: check for the known shared mailbox refresh issue and, if present, repair the profile corruption.

References:

• Sync a shared mailbox in new Outlook
• Shared mailbox is not automatically refreshing for new email in Outlook