With today’s use of e-mail you almost can’t afford to lose a single e-mail so let alone your entire mail archive, Calendar items and Contacts.
All your email, your contacts, your calendars, and almost every other detail of your life is in Outlook. To make sure you don’t lose all this in case of a hard disk crash or some other disaster, you can create backup copies of your Personal Folders (.pst) files—that’s where Outlook stores all the essential data.
Instructions for back up information on Outlook simply
Creating a backup copy of your Outlook data (or moving it to a different computer) can be as easy as copying a single file.
Step 1: Select File in Outlook.
Step 2: Click the “Info” category.
Step 3: Click “Account Settings” and choose “Account Settings” from the drop-down.
Step 4: Click the “Data Files” tab.
Step 5: For each PST file that you want to archive, highlight the data file in the Data Files list.
Note: OST files keep certain emails locally for Exchange and possibly IMAP email accounts. You can copy these OST files, but restoring data from them is not simply a matter of opening or importing the file.
Step 6: Click “Open File Location“.
Step 7: Right-click the highlighted file.
Step 8: Click “Copy” from the context menu that has shown. You can also select “Copy” on Windows Explorer’s Home ribbon or press “Ctrl-C“.
Step 9: Go to the folder in which you want the backup or copy of the PST file. Click “Paste” from the Home ribbon in Windows Explorer. You can also press “Ctrl-V“.
Step 10: Close the Windows Explorer window and select Close in the Account Settings Outlook dialog.
You can periodically backup all of your email, contacts, and calendar to a safe place. After you create the .pst file, copy it to a safe location: a USB flash drive, another hard drive, or cloud storage such as OneDrive or Dropbox. Also you can refer to article backup Outlook email to PST format. Wish you are succesful!