This guide will enable you to:
1) Back up your existing mailbox(es) using Outlook on your Windows computer.

Check:
1) There is somewhere secure to save your mailbox archive.

Backuing up the account:
1) Open Outlook.
2) Select File > Info > Options.




3) Select Advanced > Export.
4) From the box ("Import and Export Wizard") which pops up, select "Export to a file" > Next.




5) Select "Outlook Data File (.pst)" > Next.



6) Select the top level folder you wish to export > Next. "Top level folder" means the folder which contains all of the folders you wish to back up. E.g. Selecting "Inbox" will only back up the inbox and any folders contained within the inbox. As we wish to back up the entire mailbox (Inbox, Sent Items, etc), select the top most folder of the account.




7) Select a suitable location to save the backup > Finish.




8) You will be asked to protect the backup file with a password. To save the archive without a password (recommended), simply click "OK" without entering a password. This is the recommended method as: 1) users frequently forget passwords, and 2) it is trivial for anyone with access to a search engine, a brain and fingers to reveal or bypass the password. In the worst instance, if you used the same password as that used to access your email generally, it may provide an attacker with unlimited access to your mailbox and other accounts. As a result, there is little benefit in setting this. It would be preferable to encrypt the backup file after saving using a tool such as AESCrypt. Store the backup in a safe location such as your private network drive. Do not store it on an unencrypted USB drive.




9) Find the file in the location to which you saved it (the default is the desktop), and store it safely.