We have all faced this problem at least once in our lives, well, if we have used Microsoft Outlook – the best MS Office tool I have come across. We forget the password we used when exporting Microsoft Outlook mail file to a .pst file. If you forget your password for MS Outlook mail file, (.pst) just download Kernel PST Password Recovery http://www.nucleustechnologies.com/outlook-password-recovery.html, it is free and it works. Well it worked for me. There are other recovery tools but they ask for money. So, good luck if you want to use this.