One of our teams experienced a weird problem yesterday. One of the users was experiencing issues with him mailbox size. Mailbox Stats on the mailbox server (Exchange 2007) was showing his total mailbox item size as 1.3GB but the items in outlook were definitely not even close to that size as a sum of size of all items. I am sure a lot of us have already experienced similar issues already.
While taking a little closer look the team found that the problem was with the Deleted Items folder of that particular mailbox. The said folder was neither visible in outlook nor in OWA and contained most of the items in it, approximately 1 gig of data :-O. Yes, and that is why the mailbox size was exceeding the quota size limits.
We tried using Outlook.Exe /ResetFolders but that did not help either. The next step was to find out what is wrong with the deleted items folder that it is visible via powershell when Get-MailboxStatistics but not in outlook or OWA. If nothing is visible through conventional clients, the only way to manage/fix the things is to use MFCMAPI. Download latest version of MFCMAPI from http://mfcmapi.codeplex.com
Warning: MFCMAPI can cause severe damages to the mailbox if it is used incorrectly. Use this tool at your own risk.
1. Open MFCMAPI and logon to the problem mailbox.
2. Navigate to Deleted Items folder and simply highlight the Deleted Items Folder in left side pane of the utility.
3. Sort the property names in ascending order in the right hand side pane of MFCMAPI and locate the property named PR_ATTR_HIDDEN
This is a Boolean property which accepts the values as True or False. Objects with this property value set to True become invisible to clients and that is exactly what happened in our case too. For some reasons the value of this prop was set to True. Due to time constraints we could not find out the reason why it got changed.
4. The next step is to change the value to False so that the folder / object becomes visible in the client. To change the value simply double click on the prop PR_ATTR_HIDDEN and a pop up box comes up.
Check the checkbox Boolean and hit Ok button. Checking or un-checking the checkbox on above dialog box toggles the value between True and False.
Well that is it! you should get your lost folder visible back in mailbox using outlook / OWA.