A PST file (personal storage) is a personal folder file in Microsoft Outlook. In order to have a .pst file, it is necessary to have at least 1 outlook profile.
C:\Users\N A M E\AppData\Local\Microsoft\Outlook\*.pst To (re-)create a copy of your whole .pst file: 1. Close any messaging programs such as Outlook, Microsoft Exchange, or Microsoft Windows Messaging.
2. Click Start > Control Panel.
3. Double-click the Mail icon.
4. Click Show Profiles.
5. Click the appropriate profile, and then click Properties.
6. Click Data Files.
7. Under Name, click the Personal Folders Service that you want to back up. By default, this service is called Personal Folders. However, it may be named something else.
Note If you have more than one Personal Folders Service in your profile, you must back up each set of .pst files separately.
8. Click Settings, and then note the path and file name that appears.
9. Close all the Properties windows.
10. Use Windows Explorer or My Computer to copy the file that you noted in step 8. You can copy the file to another location on the hard disk drive or to any kind of removable storage media, such as a floppy disk, a CD-ROM, a portable hard disk drive, a magnetic tape cassette, or any other storage device.
How to manage .pst files in Outlook 2007, in Outlook 2003, and in Outlook 2002