Software & Apps MS Office How to Password-Protect Outlook PST Files Keep your Outlook email archives private By Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated March 18, 2020 MS Office Outlook Word Excel Powerpoint Tweet Share Email The Microsoft Outlook email program stores your messages and other Outlook files on your computer in the form of Outlook Data Files with the extension .pst. These files are commonly referred to as PST files. Outlook lets you password-protect PST files to prevent other users from unintentionally altering, deleting, or otherwise accessing these potentially sensitive files on a shared computer. Instructions in this article apply to Outlook 2019, Outlook 2016, Outlook 2013, Outlook 2010, and Outlook for Office 365. Password-Protect Access to an Outlook PST File To apply a password to an Outlook PST file: Open Outlook. On the File tab, choose Account Settings > Account Settings. Select the Data Files tab. Choose the Outlook Data File (.pst) for which you want to create or change a password, and then choose Settings. Select Change Password. If you have an Exchange account, the Change Password button won't appear. Your network password is your .pst password. In the New password and Verify password boxes, type a password of 15 characters or less. Remember your password! Microsoft can't retrieve it for you if you lose it. Write it down and keep it in a secure location. Select OK to save the new password. You've successfully password-protected the PST file. PST file passwords don't protect your system against intentional malicious attempts to access your information. To restrict access to your data, create a password-protected Windows user account for any person who uses the computer.