It is important to backup of your Outlook PST file. A Backup copy of PST file is a saver when you are unable to access your emails due to damage to PST file or deletion of file due to various reasons, such as virus infection, system formatting, application malfunction, unexpected system shut down.Steps to Create Backup of the PST file
Exit all mailing applications, such as Microsoft Exchange and Outlook.
Select Start >> Run. Type 'control panel' command in the Open box, and then use ENTER.
After doing same, Control Panel opens. Choose a Pick a category screen, select User Accounts, and move to next step.
Click twice on Mail icon.
Select Show Profiles and appropriate profile, and then select Properties.
Select Data Files.
Select the Personal Folders Service that you want to backup in the Name. This service is by default known as Personal Folders.
You can assign some other name also. In case if profile includes more than one Personal Folders Service, then backup each set of .pst files separately.
Select Settings, and then write down the path and file name that comes.
Point to be noted: As, Outlook PST file includes all the data that is saved in the MAPI folders, it can make Outlook PST file quite large. To decrease the PST file size, select Compact Now in the Settings window.
Quit all the Properties windows.
Employ My Computer or Windows Explorer to copy the file whose path you have noted in Step 8
Copy the file to some other location on the hard disk drive or to a storage device, such CD-ROM, a portable hard disk drive, etc.