Outlook 2010 Mailbox Full – Your mailbox is full, you may not be able to send or receive mail

When you start Outlook 2010, you may get the error “"Mailbox Full – Your mailbox is full, you may not be able to send or receive mail”. This may be a false notification, as it appears to a bug in Outlook 2010 when you’re running in Outlook Cached Mode.

To make sure that your mailbox is not full, you can do 1 of the following things:

  • Run “Get-MailboxStatistics alias | fl StorageLimitStatus” on your Exchange server in the Exchange Management Shell
  • Log on to OWA and hover your mouse on your name in the left upper corner. A window will appear that tells you your mailbox current size and its maximum size.
  • Log on to the server. In the Recipients Configuration, check the current mailbox size of the user, and check the quota limit (tab Mailbox settings –> Storage quotas)

Once you’ve verified that your mailbox is NOT full (so the full mailbox notification is incorrect), you should do the following:

  1. Open Outlook, click File (left top), Click Account Settings, double click your account name, and then uncheckUse Cached Exchange Mode” and finish the wizard
  2. Close Outlook. Delete your OST file. The default location for you OST-file on Windows 7 is C:\Users\user\AppData\Local\Microsoft\Outlook\. Either copy and paste the path in Windows Explorer, OR Enable Hidden Folders to view the AppData folder.
  3. Open Outlook again and enable Cached Exchange Mode again (like you did in step 1, but now recheck)
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How about this case:
Using the OWA and Outlook, it is still showing the old quota limit, however, from the EAC the user limit is no longer managed under the database limits. It was set to double the size.
No matter what we do, the user still doesn’t receive emails, and the mailbox shows on the OWA it’s full!!!
Any idea?
Exchange 2010 SP2 on Win 2008R2 SP1


It seems no one has a resolution


We had a similar situation with Exchange 2007 Ent and Outlook 2010-64.
Outlook would show the message “Your mailbox is near the maximum storage limit. Archive or delete items to create additional free space.” under the file menu. Even though, the user’s mailbox size was set to unlimited.
This fixed the problem in our case:
Using the “Exchange Management Shell” issue the following commands (quotes are required).

*** To find which database the user is using***

Get-MailboxStatistics “username” | ft Database

*** to Clean Mailbox database ***

Clean-MailboxDatabase “exchangeserver\storagename\group database”

ask users to restart outlook


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Your path is correct, but it lists “user”.. which might not be the actual username. The following path information uses a variable that should allow access for everyone without requiring them to change anything:


Worked like a charm…I’ve got 27,500 emails as soon as I unchecked ” Use Cached Mode” …Not sure where are they stuck since now !!


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Hmm, ok, I have this problem on several systems after doing a POP3 to hosted exchange migration. what happened was I manually set all the quotas to a reasonable size, much larger than needed. 25gig. But I had one user that needed much more, so I had the hosting service do some magic and up the max limit to 50gb. I had all the users email syncing at that time, I had restored their emails from the PST files and thus the local copy had all the email of say 6gb and was slowly sending them up to the exchange… Read more »

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