Software & Apps MS Office How to Password-Protect Outlook PST Files Keep your Outlook email archives private Share Pin Email Print MS Office Outlook Word Excel Powerpoint 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 February 03, 2020 You can password-protect your PST files, where Outlook keeps all mail, contacts, and calendar data. A password protects potentially sensitive files from access by others who share your 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 When you apply a password to an Outlook PST file, a prompt appears when Outlook starts or when the file is initially opened in an Outlook session. Open Outlook. Go to the File tab and select Info. Select Account Settings > Account Settings. In the Account Settings dialog box, select the Data Files tab. Choose the Outlook Data File (.pst) for which you want to create a password. Select Settings > Change Password. If you have an Exchange account, the Change Password button will not appear. Your network password is used for your .pst password. In the New password and Verify password text boxes, enter a password. The password must be between 8 and 15 characters and can include a mix of uppercase and lowercase letters, numbers, and symbols. Select OK to save the new password. Close the Account Settings dialog box.