About data files

The type of e-mail account you use primarily determines how your e-mail messages, calendar, and other items (item: An item is the basic element that holds information in Outlook (similar to a file in other programs). Items include e-mail messages, appointments, contacts, tasks, journal entries, notes, posted items, and documents.) are delivered and stored.

ShowMicrosoft Exchange Server e-mail account

If you use Microsoft Exchange Server, typically your e-mail messages, calendar, and other items (item: An item is the basic element that holds information in Outlook (similar to a file in other programs). Items include e-mail messages, appointments, contacts, tasks, journal entries, notes, posted items, and documents.) are delivered to and stored on the server.

You can also work offline or use Cached Exchange Mode. A local copy of your items is kept on your computer in an Offline Folder file (.ost) (Offline Folder file: The file on your hard disk that contains offline folders. The offline folder file has an .ost extension. You can create it automatically when you set up Outlook or when you first make a folder available offline.). The .ost file is synchronized with the Exchange server. Offline Folder files allow you to work with your items when a connection to the Exchange server may not be possible or wanted.

Your items can also be moved or archived to a Personal Folders file (.pst) (Personal Folders file (.pst): Data file that stores your messages and other items on your computer. You can assign a .pst file to be the default delivery location for e-mail messages. You can use a .pst to organize and back up items for safekeeping.). Since a .pst file is kept on your computer, it is not subject to mailbox size limits on the server. Outlook can be configured to deliver new items to a .pst file, but doing so has several disadvantages including not being able to work with your items from other computers or when using Microsoft Outlook Web Access with your Exchange e-mail account.

ShowPOP3, IMAP, and HTTP e-mail accounts

If you don't use an e-mail account on an Exchange server, your e-mail messages, calendar, and other items are delivered to and stored locally in a Personal Folders file (.pst) (Personal Folders file (.pst): Data file that stores your messages and other items on your computer. You can assign a .pst file to be the default delivery location for e-mail messages. You can use a .pst to organize and back up items for safekeeping.) called Outlook.pst. Outlook.pst is the default data file name.

Working with data files

ShowData file types

In Microsoft Office Outlook 2003, a new Personal Folders file format, called Microsoft Outlook Personal Folders file (.pst) is introduced that offers greater storage capacity for items and folders and supports multilingual Unicode (Unicode: A character encoding standard developed by the Unicode Consortium. By using more than one byte to represent each character, Unicode enables almost all of the written languages in the world to be represented by using a single character set.) data. A file created in the Microsoft Outlook Personal Folders file (.pst) format is not compatible with earlier versions of Outlook and cannot be opened in a previous version of Outlook.

To create a data file that is compatible with earlier versions of Outlook, use the Microsoft Outlook 97-2002 Personal Folders file (.pst) format. This file format is the same as the format that was available in earlier versions of Outlook. It does not support multilingual Unicode data and offers the same storage capacity for items and folders that was available in earlier versions.

ShowData file locations

To see where default store and additional data files are kept on different versions of Microsoft Windows, see the "Outlook file locations" topic. Keep these points in mind:

ShowData file security

  • When you create a .pst, you can assign a password to the file. A password improves security and reduces the ability of others to view your data. You can select the Save this password in your password list to avoid being prompted for the password each time you open the file.

Use strong passwords that combine uppercase and lowercase letters, numbers, and symbols. Weak passwords don't mix these elements. Strong password: Y6dh!et5. Weak password: House27. Passwords should be 8 or more characters in length. A pass phrase that uses 14 or more characters is better. For more information, see Help protect your personal information with strong passwords.

It is critical that you remember your password. If you forget your password, Microsoft cannot retrieve it. Store the passwords that you write down in a secure place away from the information that they help protect.

 Note   If your Windows user account is not password-protected or other people have access to your Windows user account, do not use the Save this password in your password list option.

ShowUse a data file to organize or back up items

  • You can create additional data files if you want to organize Microsoft Outlook items into specific folders. For example, you might want to keep all messages from a specific company in a separate data file. When you create the data file, you can use any name for the file. The default name is Personal Folders(1).pst, Personal Folders(2).pst, and so forth. You can use any name for the folder associated with that data file. The default name for the folder that appears in the Outlook Folder List (Folder List: Displays the folders available in your mailbox. To view subfolders, click the plus sign (+) next to the folder. If the Folder List is not visible, on the Go menu, click Folder List.) is Personal Folders.
  • You can also use AutoArchive to move items to a an archive file (Archive.pst). Unlike exporting, where the original items are copied to the export file but are not removed from the current folder, archiving copies items to the archive file and then removes them from the current folder. AutoArchive allows you to set up a schedule and archive multiple folders at the same time at set intervals.
  • A utility called PST Backup enables you to make an exact copy (in the same file format) of a .pst data file, copy the backup file to your hard disk or to a network share, and specify a time interval at which Outlook will prompt you to back up a file. Use the backup file to restore the current .pst file in the event that it becomes corrupted or deleted. To use the utility, you must download it from the Microsoft Office Online Web site.
  • When you remove items from a Personal Folders file, your file size will not decrease unless you compact the file.

ShowUse a data file to distribute information

  • You can use a data file to make information, such as Contacts, available to another computer you use or to people you work with. The easiest way to do this is to export (copy) the information to a .pst file using the Import and Export wizard.
 
 
Applies to:
Outlook 2003