Issue: How to protect Outlook *.pst file with a password.
To set a password on an Outlook pst file:
1. Go to the top level of your folder, where Outlook Today is found. The folder name may include “Outlook Today” or your email account name.
2. Right click on it and choose Properties (Data File Properties in Outlook 2010)
3. Click the Advanced button
4. Click Change Password
5. Leave the Old Password field blank and enter a New Password and verify password.
Leave the Save this password in your password list box unchecked. This prevents the password from being cached (otherwise, anyone can open the data file on this computer). You will need to type it each time you run Outlook.
If you are changing an existing password, type both the old and new passwords in the respective fields. When you open Outlook, you’ll be asked for the password. This will prevent someone from opening Outlook and viewing your email. If Outlook is open, anyone using your computer can access your email – to protect it, you either need to close Outlook or lock the desktop when you walk away by pressing the Windows+L key.