After you set a password on an Outlook Data File (.pst), it is a good practice to change the password periodically.
Click the File tab.
Click Account Settings, and then click Account Settings.
On the Data Files tab, click the Outlook Data File (.pst) for which you want to create a password, and then click Settings.
Click Change password.
Note The Change Password button does not appear if you are using an Exchange account. Your network password is used to access your Exchange account and information.
In the Change Password dialog box, in the New password and Verify password boxes, type the new password. The password can be up to 15 characters and is case-sensitive.
Learn more about password best practices
Use strong passwords that include and mix of a minimum of eight uppercase and lowercase letters, numbers, and symbols such as Y6dh!et5. A longer and complex password helps improve password protection.
Important It is critical that you remember your password. If you forget your password, Microsoft cannot retrieve it. Any password that you write down should be kept in a secure location, away from the information that it helps protect.
Click OK to set the password.
There is no logon password for the Outlook program itself; the password you set with the instructions here protects only the Outlook Data File (.pst) that you use in Outlook.
Your computer can remember your password so that you don’t have to type it in each time that you pen the Outlook Data File (.pst). If your Microsoft Windows user account is password protected, and no other person has access to your Windows user account, you can select the Save this password in your password list check box after you verify your new password.
When you set an Outlook Data File (.pst) password, it is set for the entire file. You cannot set a password for individual folders within the Outlook Data File (.pst).