How to Encrypt Microsoft Outlook PST Files
Many years ago, I figured out how to secure my Microsoft Outlook PST files using TrueCrypt. TrueCrypt may now be defunct, but there are a couple of successors like CipherShed, TCNext and VeraCrypt. The steps below will work with them and any Microsoft PST files. This was written for Microsoft Outlook 2003, but I have successfully used this method successfully with most versions of Outlook (2007, 2010, 2013) since then.