To get backup of .PST Files in Microsoft Outlook, it describes given below few of way which is more reliable and right for Microsoft outlook problems concerned.

1. How to Move Outlook .PST File One Place to Another
Outlook PST File (Personal storage Table) is an Open possessory file
format which is used to store copies of Message, Calendar, some other
Microsoft software like as Microsoft Exchange client and window
messaging. It .PST File is controlled by Microsoft.
To get backup of .PST Files in Microsoft Outlook, it describes given below
few of way which is more reliable and right for Microsoft outlook problems
concerned. There are two kind of way which is more use fullfor you.
Way 1 –
A) - Download to Microsoft Personal Folders Backup Add-in from
Microsoft's Download Center.
B) - Click on the "Download button" toStart downloading the file.
C) - Browse to the PST folder and look on pfbackup.exe file.
D) - Do double-click to open it and run the installation.
E) - Follow the on-screen instructions and Finished the installation
of add-in.
F) - Reboot your System.
G) - Click the Backup button and it will open the Outlook Personal
Folders Backup dialog box and customize your backup options
Way 2-
H) You may just copy & paste the PST file data to another place in
your computer.