XADM: How to Apply Mailbox Message Size Limits to Multiple Mailboxes

You can use the directory export function in the Microsoft Exchange Server Administrator program to limit the amount of storage used by messages sent to or from one or more mailboxes.

To use the directory import function to apply storage limits, you create a Comma Separated Values (CSV) file, create new columns in the CSV file, and then import the CSV file into the Exchange Server directory. The values you include in the new columns are used to create new attributes for the existing mailbox objects in the directory.

To apply mailbox message size limits to multiple mailboxes:

1.	Export the mailboxes from the directory to a CSV file.
2.	Using Microsoft Excel, open the CSV file, and add columns for the Incoming Message Size Limit and Outgoing Message Size Limit, as needed. The titles of the new columns must appear on row 1 of the spreadsheet, and spaces between words in the titles are valid.
3.	Enter the values for the Incoming Message Size Limit and Outgoing Message Size Limit in the appropriate cells. Exchange Server interprets the values entered in the message size limit columns as kilobytes (KB). For example, a value of 50 in an Incoming Message Size Limit cell is interpreted as a limit of 50 KB.
4.	Save the CSV file.
5.	Use directory import to import the CSV file into the directory.

Message limits are now set on the mailboxes, and may be verified on the Limits page of the mailbox properties.