I forgot my Personal Folders file (.pst) password
If you have password protected a Personal Folders file (.pst) and did not select the Save this password in your password list check box, a dialog box similar to the following appears when you try to open the .pst file in Microsoft Outlook.
If the password you type in the Password box is incorrect, you get the following error message: The password you have typed is incorrect. Retype the password.
You have entered an incorrect password.
To open the .pst file, you must enter the correct password. Remember that .pst passwords are case-sensitive. Try to remember whether the password that you assigned used uppercase and lowercase letters and make sure that your CAPS LOCK key is not on.
Passwords cannot be reset or recovered if lost. Microsoft is not able to retrieve lost .pst passwords.