This is an odd one that I haven't been able to find a resolution for yet. Our organisation uses Microsoft Exchange Online (O365) and I have a user who created a mail folder on the same level as the Inbox. In that folder she created a number of sub-folders for all of the legal matters she is working on. Over the past week or two she had been filing inbound email into these folders manually, but on Friday last week, the parent folder (and subsequently all of the sub-folders) disappeared from the Folders pane in Outlook.

I have expanded every single folder, started Outlook in safe mode, reset the Nav Pane, rebuilt the entire profile by creating a new one and waiting for the sync to complete. Cleared all view filters and pretty much everything that Googling suggests and haven't been able to brink them back into view.

The thing is though, that if you right-click an email in the Inbox, you can choose to Move To and a few of the most recent sub-folders appear in the list. If you click one of them, the email disappears from the inbox, so it is being move successfully.

When we search the whole mailbox for that email, it shows up in the search results, and the "In Folder" column lists the name of the folder. Great! But it doesn't list the path to that folder, so I still cannot seem to locate the folder or it's parent anywhere.

Does anyone have any fixes or suggestions for trying to locate these folders? Maybe a way of showing the folder path in the search results or something...

Thanks in advance


I've checked "Folder Size" of the mailbox (the top-most folder), and in the list of folder and sub-folder size, it is listing ALL of the missing folders. So the data definitely is there. What's even more confusing is that none of these folders are visible in OWA either. Strange right?

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1 Answer 1


OK - so after mixing up my Google search terms a bit, I came across the fix. Whilst there is a lot of people complaining about the same issue with Outlook 2010, there is no Microsoft documentation on how to fix it.

The page I found the solution is http://desigeek.com/blog/amit/2007/01/17/solved-case-of-the-invisible-folder-in-outlook-and-exchange/.

To summarise

  1. You will need to download the MFCMAPI tool - which isn't available at the Microsoft link in Amit's blog post (see above URL) anymore, but is available at https://github.com/stephenegriffin/mfcmapi/releases/latest.
  2. Once you have the correct 32-bit/64-bit version downloaded (most users will need the 32-bit version), decompress the download, open the directory and run the executable (I can confirm that it's safe!).
  3. Click OK to the release notes, then click the Session menu and choose "Logon...". Select the Outlook profile you wish to repair.
  4. Double-click the mailbox you wish to open (I have five mailboxes, so usually it'd be your own email address), expand Root-Mailbox, IPM_SUBTREE.
  5. Locate and select the folder you're needing to restore, right-click the PR_ATTR_HIDDEN property in the right-hand pane and select Edit Property. Remove the checkbox for Boolean, click OK.
  6. Close the current window, click on the Session menu and choose "Logoff". Exit the application completely.

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