OST Reached Maximum Size
Email Clients such as Microsoft Outlook are limited to a 2 Gigabyte maximum size for the Offline folder store (OST) and Local Personal (PST) store files. Therefore, the normal quota for the Exchange Mail System is two gigabytes per user.
Microsoft Outlook displays the Mailbox Cleanup Wizard when the quota hard limit has been reached (when using Microsoft Outlook). The mailbox cleanup utilities provide a rich set of options for searching and archiving messages to a local store (PST) file. Please note that microsoft outlook 2003 and 2007 does not have this limitation.
For more detailed information about archiving items in Outlook and using local folders, visit following URL :
