One of the most popular ways for a virus or other malware to spread is by means of e-mail. However, because most virus attacks are sent via a PC and not a server application, viruses must find a way to attach themselves to your e-mail sending system. When using Microsoft Outlook this is done by corrupting the Outlook inbox and the database for it which is known as the PST file.
Corrupted PST repair can be accomplished in many ways but the basic technique is to use a mirror file. A mirror file is simply a clean non-corrupted representation of your Microsoft Outlook PST database. One can either extract the core information from their corrupted Outlook file system and install it into the clean new PST file or one can use the newer file as a basis and rewrite the header instructions on your PST file. These are the two PST repair methods most in use.