The PIF extension shows to a file, that means a “program information file”. A system file, that windows uses since it was created. It was meant to to store information on how to run programs. They are still used in the Windows that we use now, but the file is one of those witch you do not really need to know. If you try to run it, you will not get anything from it, but the file helps other programs to run.

If you receive a PIF file in an email it is probably a virus. You should check who has send you the email, and if you are not sure who is it from just delete it. Even if you know who the sender of the email is, but you do not know what to do with the file, then delete it also. It is very probable that the person who the email is from, does not know that he or she has a virus that is sending the emails by itself. If you are really sure, that you know why this file is in your email and you know what to do with it then it is safe for you to open the file. Your anti virus program should protect you even if the file is infected. But be careful anyway.

In the first versions of Windows, the PIF file consisted only of the basic section and the other sections were added later, since Windows 3.0. The data of the basic section is always placed at the beginning of the file, and the minimal length of the PIF file, that will still be accepted by all Windows versions is 0187h bytes. All Windows versions, except for NT and 2000, normally accept PIF files of length 0171h bytes.