Before making any major changes to outlook or your Outlook settings it is always a good idea to perform a backup of your pst file. This file contains all your personal Outlook folders and email. Also it’s pretty easy to do.
Outlook 2013
Click the File Tab
Click Open and Export
Click Import Export
Click Export To File, and then click Next.
Click Outlook Data File (.pst), and then click Next.
Select the folder to export, and then click Next.
Click Browse, and then select the location where you want the new .pst file to be saved.
In the File Name box, type the name that you want to use for the new .pst file, and then click OK.
Click Finish.
Outlook 2010:
Click the File tab.
In the Outlook Options window, click Advanced.
Click Export.
In the Import and Export Wizard, click Export to a file, and then click Next.
Click Outlook Data File (.pst), and then click Next.
Select the folder to export, and then click Next.
Click Browse, and then select the location where you want the new .pst file to be saved.
In the File Name box, type the name that you want to use for the new .pst file, and then click OK.
Click Finish.
Earlier version of Outlook:
On the File menu, click Import And Export.
Click Export To File, and then click Next.
Click Personal Folder File (.pst), and then click Next.
Click the folder to which you want to export the .pst file, and then click Next.
Click Browse, and then select the location where you want the new .pst file to be saved.
In the File Name box, type the name that you want to use for the new .pst file, and then click OK.