1.Open the Active Directory Users And Computers management console.
2.Select the appropriate user account object.
3.Right-click the user account object, and select Properties from the shortcut menu.
4.Click the Exchange General tab.
5.Click Storage Limits.
6.The Storage Limits dialog box opens.
7.Uncheck the Use Mailbox Store Defaults checkbox so that you can configure your own mailbox storage settings.
•If you want to send a warning to the user when the user’s mailbox reaches the storage limit, enable the Issue Warning At (KB): checkbox and specify the appropriate value.
•If you want force the user to clean up a mailbox that has ignored an issued warning, enable the Prohibit Send At (KB): checkbox and then specify the desired value.
•If you want to force the user to clean up a mailbox in order to receive/send new messages, enable the Prohibit Send And Receive At (KB): checkbox and set the appropriate value for the option.
8.Uncheck the Deleted Item Retention checkbox if you want to define your own Deleted Item Retention settings.
9.Click OK.