Microsoft Outlook error message: 'Mailbox Size Limit exceeded'

An Exchange administrator keeps receiving an error message stating 'Mailbox Size Limit exceeded.' See what to check before taking action.

My Exchange Server has been sending my users this message:

"Mailbox Size Limit exceeded: This notification is to inform you that your mailbox size has reached the defined limit for Prohibiting Send.

Allotted Mailbox Size: 200 MB
Prohibit Send Limit: 90% of your allotted Mailbox size."

The default mailbox storage is 512 MB for all users and we've even adjusted the mailbox size for a specific user to 612 MB. However, users continue to get this notification. I can't find anything about a 200 MB limit being set. Do you have any ideas?

I would first look to see where you're looking for the mailbox size? If you're searching within Exchange System Manager, you won't get an accurate idea of folder size. I'd suggest right-clicking the mailbox from within Outlook to see what the mailbox size is according to Outlook. I've frequently found that the "conflicts" folder contains upwards of 200-300 MB of data.

If this doesn't work, you should know that mailbox limits really only restrict the size of the priv.edb portion of the Exchange database. Storage limits don't affect the priv.stm file. For example, if the mailbox shows as 150MB in Exchange System Manager, the mailbox could represent 150 MB of space in the priv.edb file and another 100 MB of space in the priv.stm file. This means the mailbox is really using 250 MB of storage space.

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Expert tip: What to do when you get the error "Outlook error: The operation failed. An object could not be found."


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