Classic Outlook Not Syncing Emails or Folders

Symptoms

You may experience one or more of the following:

• New emails are not appearing in Outlook
• Sent emails are missing
• Folders are not updating
• Shared mailboxes are not syncing correctly
• Outlook displays older emails but not recent ones
• Outlook appears to be connected but does not show current data

Resolution

Step 1: Disable Cached Exchange Mode

1. Open Outlook.
2. Select File.
3. Select Account Settings.
4. Select Account Settings again.
5. Double-click your email account.
6. Uncheck Use Cached Exchange Mode.
7. Select Next.
8. Select Done.
9. Close and reopen Outlook.

After Outlook reopens, it will connect directly to Microsoft 365 instead of using the local cache.

Step 2: Verify Email Synchronization

After reopening Outlook:

1. Send and receive a test email.
2. Verify new emails are appearing.
3. Confirm folders are updating correctly.
4. Verify any shared mailboxes are syncing properly.

Additional Troubleshooting

If the issue continues:

1. Repeat the steps above and re-enable Cached Exchange Mode.
2. Set the Mail to keep offline slider to All.
3. Restart Outlook.
4. Allow time for Outlook to fully synchronize.

Why This Works

Cached Exchange Mode stores mailbox data locally on your computer to improve performance. Occasionally, the local cache can become outdated or out of sync with Microsoft 365.

Disabling Cached Exchange Mode forces Outlook to retrieve mailbox information directly from Microsoft 365, which can help resolve synchronization issues.

Contact IT If

• Outlook is still not syncing after completing the steps above.
• Emails are missing from Outlook but appear in Outlook on the Web.
• Shared mailboxes continue to have synchronization issues.
• Outlook displays an error message during synchronization.