A password can be set for an Outlook Data File (.pst) to help prevent unintentional intrusion by other people who share your computer. When a password is used, a password prompt appears when Outlook starts or when the file is first opened within an Outlook session. Security Note: Outlook Data File (.pst) passwords aren't intended to provide security against intentional malicious attempts to access your information. For a better way to restrict access to your data, create a password-protected Windows user account for any person who uses the computer. For more information, see Windows Help and Support. Newer versions Office 2007 Set or change the password for a .pst file After you set a password on an Outlook Data File (.pst), it's a good ...