You discover that one or more items are missing from a folder in a Microsoft Exchange Server mailbox in Microsoft Office 365 Dedicated.
This issue occurs for one or more of the following reasons:
Items are deleted incorrectly or unintentionally.
A client configuration or a third-party tool deletes items unexpectedly.
If a user reports a deleted or missing item, try to determine whether one of the following scenarios applies:
The user wants to recover the item.
This is an ongoing issue that the user is experiencing, and the cause of the deletion should be investigated.
To resolve this issue, follow these steps:
Check the Deleted Items folder and the Deletions folder in Microsoft Outlook. For more information about how to do this, click the following article number to view the article in the Microsoft Knowledge Base:
3139942 How to recover deleted items in Office 365 dedicated/ITAR
If the item cannot be found or if the deletion is a symptom of a recurring issue, obtain all the details to correctly scope the case. This information helps make sure that you take the correct steps to investigate the issue and that the user has followed the troubleshooting steps from Knowledge Base article 3139942 . (There should be a missing example item about which the user can provide information.) If you want assistance from Microsoft about this issue after you perform the following troubleshooting steps, please use the Exchange Online topic and the Calendaring/Mailbox Content problems sub-topic when you submit a support incident online to Microsoft Online Services Support, or contact Microsoft Online Services Support by telephone.
Note If the user's calendar is managed by a delegate and if the example item has been changed by the delegate, you can view the mailbox audit logs to obtain more details about the item. For more information about how to do this, click the following article number to view the article in the Microsoft Knowledge Base:
2792663 How to investigate missing or unexpectedly updated mailbox items by using mailbox audit logging in Office 365 dedicated
Based on the details that you collect in step 2, search for known issues in the Microsoft Knowledge Base:
Run the Microsoft Outlook Configuration Analyzer Tool (OCAT) on the user's computer. This tool generates a detailed report of the Outlook profile and highlights known configuration problems. If the generated report does not include steps to resolve the issue, and if you contact Microsoft Online Services Support by online submission or by telephone, you should provide the XML output report.
For more information about OCAT, click the following article number to view the article in the Microsoft Knowledge Base:
2659007 Outlook Configuration Analyzer Tool information