When it comes to data on your computer, email messages come as a top priority for the data recovery effects, especially if they include business and commercial information. Because your messages are so important, it is understandable that you need to be proactive, foresee the possible coming computer crash, and perform frequent backups for your Microsoft Outlook profile and messages.
In the event of a hard drive crash or virus attack, a backup of your Outlook .PST file allows you to keep a copy of all your important email messages. Even if you lose your messages completely on your master disk, you can import them from the .PST file after you re-install Microsoft Outlook in several easy steps.
So, note that you don't have to transfer each individual email to your external hard drive. Microsoft Outlook can export all of your messages to a single file for easy transport. Using Import and Export Wizard, convert the content of your mailbox to a personal folders, or PST, file; you can import this file into any email client that supports Microsoft Outlook. If you want to copy only business-critical messages to your other drive, create a new folder in your inbox and move the relevant emails to the new location. You can select to export that particular folder in the wizard.
Backing Up Outlook Data to External Drive
Step 1: Open your account in Microsoft Outlook. Click "File," "Open & Export," then "Import/Export."
Step 2: Select "Export to File" in the Import and Export Wizard and then click "Next."
Step 3: Click "Outlook Data File (.pst)" and then click "Next." Choose "Inbox" as the folder to export, or expand "Inbox" and select the appropriate folder. Click "Next."
Step 4: Connect the external drive to your computer. Click "Cancel" if a dialog box appears on-screen.
Step 5: Click "Browse," select the external drive from the list of storage devices and then create an easy recognizable name for your backup file. Click "OK."
Step 6: Click "Next," then "Finish." To secure the messages, enter a password when prompted and then click "OK. Otherwise, click "Cancel."
Restoring Outlook Data from External Drive
Step 1: Connect the external hard drive or USB flash drive holding the backed up .PST files to the computer. Wait for Windows to configure the external device as a storage device on your computer.
Step 2: Click "Start" and then "Computer." Double-click the drive letter of the external hard drive or USB flash drive. Navigate to the folder on the device that contains the .PST file.
Step 3: Highlight the .PST file. Right-click the file name, then click "Copy" on the pop-up menu.
Step 4: Navigate to the "C:\Users\USER_NAME\AppData\Local\Microsoft\Outlook" folder where "USER_NAME" is the name of the Windows user account for which to import the Outlook profile and messages. Right-click inside the folder window, then click "Paste" on the pop-up menu.
NOTE: The provided path might be different, depending on the Windows software version. For example, it might be C:\Documents and Settings\USER\Local Settings\Application Data\Microsoft\Outlook\,or similar, where [USER] is your username on the Windows computer. If you are not sure, search for Outlook folder through the built-in search function in the Windows.
You may need to take ownership of the files on the old hard drive, before being able to access them. Windows will prompt you if necessary and do this for you. You may also need to show hidden items from the File Explorer in Windows 8 in order to see the relevant folders. To do this click on “View” and then tick the box marked "Hidden items" in the Show/Hide section towards the right hand side.
Step 5: Launch Microsoft Outlook on your computer. Click "File" on the ribbon bar and then click "Import and Export."
Step 6: Click the "Import from another program or file" option and then "Next." In the "Import a File" window, select the file type "Outlook Data File (.pst)." Click the "Next" button.
Step 7: Click the "Browse" button in the "Import Outlook Data Files" dialog box. Navigate to the folder where you copied the .PST file from the external storage device. Highlight the file name, then click the "Open" button.
Step 8: Click and select the "Replace duplicates with items imported" option. Click the "Next" button.
Step 9: Wait for Microsoft Outlook to import the profile and messages from the .PST file. Once the import process finishes, click the "Finish" button. Outlook displays the messages in the "Inbox." Outlook also adds name and email address information from the .PST file to the current profile.
Sources and Additional Information: