Personal Folders (.pst) file

.pst, which stands for Personal Storage Table is a filename extension associated with Personal Folders files used with certain Microsoft products. Personal Folders (.pst) files are used to store local copies of messages, calendar events, and other items within Microsoft Microsoft Exchange Client, Windows Messaging, Microsoft Outlook, and Microsoft Outlook Express.

Overview

While in Microsoft Exchange Server, the messages, calendar, and other data items are delivered to and stored on the server. In standalone applications (Microsoft Outlook, for example), the messages, calendar, and other data items are delivered to and stored locally in a Personal Folders (.pst) file that is located on the computer. The file does then no longer count in the size of the mailbox used. By moving files from a server mailbox mail in the .pst files users can free up storage space on their mailserver.cite web
url=http://office.microsoft.com/en-us/outlook/HA012308901033.aspx#1b
title=Introduction to Personal Folders files (.pst)
publisher= Microsoft.com
accessdate=2008-10-04] To use the .pst files from another location you need to be able to access the files directly over a network from your mail client.

When data files like email messages are added to a .pst file its filesize is automatically adjusted by the mail client if needed. When mail is deleted from a .pst file the size of the .pst file will stay the same creating space to hold future data item. To reduce the size of .pst files you need to compact them. [cite web
url=http://office.microsoft.com/en-us/outlook/HP100807041033.aspx
title=Reduce the size of a .pst file
publisher=Microsoft.com
accessdate=2008-10-04 ] Password protection can be used to protect the content of the .pst files. [ cite web
url=http://office.microsoft.com/en-us/outlook/HA012308911033.aspx#2
title=Create a .pst file in Outlook 2003/Office Outlook 2007 format
publisher=Microsoft.com
accessdate=2008-10-04 ]

Support

The Personal Storage Table format is supported by several Microsoft client applications including Exchange Client, Windows Messaging, Microsoft Outlook, and Microsoft Office Outlook. Mozilla Thunderbird has the ability to import PST files.

Versions

Outlook 97

Starting with Microsoft Outlook 97 the Personal Storage file is encoded in ANSI format. It has a maximum file size of 2 GB. If the file exceeds this size it will become corrupted. This format is supported by Microsoft Outlook 97, Outlook 98, Outlook 2000, Outlook 2002, and Outlook 2003 Internet Message Access Protocol Version 4rev1 (IMAP4) accounts and HTTP accounts. [ [http://support.microsoft.com/kb/830336] ]

Outlook 2003

Starting with Outlook 2003 the Personal Storage file is encoded in unicode format. It allows a user-definable maximum file size up to 33TB that exceeds the previous limit of 2GB. This format is supported by Microsoft Outlook 2003 and Outlook 2007. [cite web
url=http://support.microsoft.com/kb/830336
title=The .pst file has a different format and folder size limit in Outlook 2007 and in Outlook 2003 (KB830336)
date=2007-02-05
publisher=Microsoft
accessdate=2007-03-05] [cite web
url=http://support.microsoft.com/kb/832925/
title=How to configure the size limit for both (.pst) and (.ost) files in Outlook 2007 and in Outlook 2003 (KB832925)
date=2007-02-13
publisher=Microsoft
accessdate=2008-04-09] A file that is created in the personal folders format in Outlook 2003 or Microsoft Office Outlook 2007 is not compatible with earlier versions of Microsoft Outlook and cannot be opened by using those older versions.

References