Mailbox limitations in Exchange 5.5 vs. Exchange 2003
We have an account on our Exchange 5.5 Server that is set up to log all incoming and outgoing e-mails. Basically, every e-mail that comes in or goes out passes through this account and is logged. The mailbox is set up to deliver to a .pst file on that server. The problem is that we usually reach a limit and the mailbox stops delivering to the .pst inbox at around 16,000 emails. We have no limitations on mailbox size because the majority of the emails go to the users .pst on their local machine. Why is there a limit on the .pst inbox? Is this just a limitation with Exchange 5.5? Is the size increased on 2000 or 2003?
A personal store (pst) file is an Outlook data storage file, not an Exchange data storage file. The 2GB size limit on .pst files is in all versions of Outlook (and the Exchange client) prior to Outlook 2003; in other words, Outlook 2002 (sometimes referred to as Outlook XP) and earlier have a max size of 2GB for the personal store file.
Microsoft Office Outlook 2003 no longer has this limit and offers a theoretical limit of 33 Terabytes. Other changes have been made to the .pst and offline store (OST) architecture in Outlook, as well. For example, the old format had a limit of 64,000 items per folder whereas the new format supports unlimited items. Finally, the old format uses ANSI to store data whereas the Outlook 2003 .pst data is stored in UNICODE.
If you are using or switch to Outlook 2003, you can convert your old .pst file to the new format. To do this, you can create a new .pst file that uses the new format and then either:
1. Open both files in Outlook 2003 and drag-and drop the folders from the old file to the new file.
2. Use the Outlook Import Wizard to move the data. See the Outlook help file for details on how to do this.
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This was first published in January 2004