Exchange Online - Find Lost Emails, Troubleshoot Missing Emails


  • I have lost some email; how can I find or recover it?


  • Oregon State University
  • Exchange Email


There are several possible reasons that an email might be missing:

  • The message never arrived in your mailbox for various reasons
  • The message was automatically deleted by a retention policy
  • The message was automatically archived by an archive policy
  • The message was deleted by someone with full mailbox access
    • If the mailbox is a shared mailbox, the item will be in the Deleted Items folder of the person who deleted it
  • The message was accidentally archived by pressing the Archive button or pressing Backspace
  • The message was marked as junk - automatically or by you - and is now in the Junk mail folder
  • The message (or its folder) was accidentally moved via drag-and-drop to another folder
  • The message is stored in a PST file that is no longer connected to the Outlook profile
  • The message is stored in another mailbox that is no longer connected to the Outlook profile
  • The message is in your mailbox on the server but Outlook (or other email client) has not synchronized it to your computer yet
  • The message was removed by a device you use to access your email (e.g. a mobile device)


Message Never Arrived

If you never received the missing email, ask the sender to confirm they sent it to the correct address, and to check their Inbox for a bounce error message. If the sender is not able to send to you and you are unable to determine why, contact the Service Desk or your IT support team to investigate; they can check mail delivery logs to troubleshoot the issue.

Use "Search" in Outlook on the Web

If you know you received a message but now can't find it, try doing a search via Outlook on the Web. When you access your mailbox via Outlook on the Web, it rules out a number of possible issues. If the message is in your mailbox, you will be able to find it in Outlook on the Web.

To search via Outlook on the Web:

  1. Open a web browser and visit: 
  2. Login as
  3. Click on the Search bar at the top and enter a name, subject or other message body text to search for; make sure that "All" is selected to search all folders

The above steps will search all folders in your primary mailbox. It will not search your Online Archive (see below), nor will it search in any additional mailboxes you usually access.

The Online Archive is like another mailbox, and is different from the "Archive" folder that shows in your folder list. To search the Online Archive:

  1. In the folder list on the left, you should see a folder named "Online Archive - Your Name"; select this folder to expand the set of folders within it
  2. Select a folder within the Online Archive
  3. The search bar at the top of the screen should now show "Search archive"
  4. Enter a name, subject or other text to search for
  5. In the dropdown menu to the left of the search bar, select "All folders in archive"

Note: You cannot view items in the top level of your Online Archive via Outlook on the Web. To view those items, you need to access your Online Archive via Outlook. You can then move the items at the top level to a subfolder to make them visible in Outlook on the Web. If you don't have Outlook installed on your local computer, you can use Outlook in Citrix Apps.

Check Deleted Items

Even if you don't think the messages were deleted, checking the Deleted Items folder is a good idea. It's easy to accidentally delete a message, either by clicking the delete option in the folder list (in Outlook on the Web) or pressing the Delete key (Outlook or Outlook on the Web).

Messages you (or someone else with full mailbox access) deleted within the past two weeks will be listed in the Deleted Items folder unless the Deleted Items folder has been purged

To recover deleted items, see: Exchange Online - Recover Deleted Items

Note that if you use Outlook to delete messages in a shared mailbox, by default the messages go to your Deleted Items folder, not the Deleted Items folder for the shared mailbox. For more information, see:

Add Files or Other Mailboxes Back to Outlook Profile

Sometimes messages go missing because they are stored in a PST file or additional mailbox that is no longer linked to your Outlook profile. This can happen due to any of the following:

  • Using a new or different computer
  • A new Outlook profile was created for some reason, i.e. for troubleshooting
  • Office was uninstalled and reinstalled
  • The computer has been reconfigured 

To add a PST file to Outlook:

To add an additional mailbox to Outlook:

To add an additional mailbox in Outlook on the Web:

Review Archive Policies and Retention Policies

If messages are disappearing unexpectedly from a folder, you may have an archive policy or retention policy that needs to be adjusted. Archive policies move messages to the Online Archive, after which you can still access them in Outlook and Outlook on the Web, but not from a mobile device. Retention policies delete messages.

To check policies on a folder:

  • In Outlook
    • Right-click on a folder and select Properties
    • Select the Policy tab
    • The Retention Policy is showed at the top, and the Archive Policy at the bottom
    • Both policies will usually be set to "use parent folder policy". The default policy for most folders is to do nothing. If you see a different policy set, this could be causing issues and you can change it back to "use parent folder policy".
  • In Outlook on the Web
    • Right-click on a folder and mouse over "Assign policy"
    • The default for both archive and retention is "use parent folder policy". You can select a different policy or set it to "use parent folder policy".

Troubleshoot Mobile Devices

Sometimes issues with a mobile device can cause problems in the Exchange mailbox. To rule that out as a possibility, you can turn off your mobile devices or remove your email account from them. If you don't have access to a mobile device, you can still remove it from your account by following the steps in Method 2 here: Exchange - Phone Not Syncing

Note: Any email client configured to use POP to fetch messages can potentially remove items from your mailbox. POP is not common and not recommended.


For assistance, contact the Service Desk.


Article ID: 109423
Mon 6/8/20 11:16 AM
Tue 11/1/22 4:49 PM