Outlook 2016: Some unread messages do not appear in Inbox

Question

At random during the day one of my users Outlook is not show all unread messages in the Inbox. For example, in Outlook the unread message count would show as 2 unread emails. same on his iPhone. However in the Inbox only one unread message appears. If he clicks on another folder then back to Inbox it appears. Or if he toggles between the All and Unread buttons the unread email appears. This occurs at random with different emails. The behavior is as though a screen refresh is required to show the unread email. But this occurs at random, not with all unread messages.

Steps done so far: - Reset the views - Created a new Outlook user profile Outlook is connected online to an on-premise Exchange 2016 server.

Answer 1

Sorry for the delay, I didn't see notice of your response.

Outlook is 16.0.5110.1001. When you say updated to the latest version of the desktop client, are you referring to the latest patches?

Nothing has been changed in the environment or on the client, except of disabling some unneeded add-ins but this was done in effort to troubleshoot the existing issue. One of which is an anti-virus client in. The add-ins currently running are the bare minimum needed.

It may be difficult to have the user use their Outlook in safe/mode throughout the course of the day, because the issue is intermittent we don't know exactly what triggers the issue. And not having the add-ins would affect their workflow.

The Outlook repair is a good approach. I will try that next.

Just to note I have also tried creating new Outlook profile and resetting the views with no success.

I will try to get that done today and report back tomorrow.

Answer 2

Hi @Ben Lan ,

At random during the day one of my users Outlook is not show all unread messages in the Inbox

What's the version of your Outlook 2016(File>Office account>About Outlook), please first ensure that you have updated to the latest version of Outlook desktop client.

Did this issue occurred on a specific user only? If so, did the user have any differences with others(such as client version, internet or others)?

According to your description, considering the issue occurred only recently, have you performed any specific operations before it(such as install any programs or add-ins)?

Based on my research, it may be affected by any antivirus programs or add-ins, it's suggested to close your antivirus programs temporarily and restart your Outlook in safe mode to check if the issue has any difference(windows + R> type "outlook.exe /safe">enter).

Also, the corrupted outlook client may also cause it, we could also try to repair your Outlook to check if it could work normally after that.

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Answer 3

User never responded and since then we have replaced his computer due to other performance issues.

I will close out this question.

Thanks for your assistance.