If you also want to backup all Office 365 emails in such formats which are easily accessible in an offline environment, then you need to download Office 365 mailbox as PST (which is accessible into Outlook), EML (which accessible into Thunderbird, Windows Live Mail, and so on) Downloading Office 365 Emails in Local System – Why it is Necessaryĭownloading Office 365 emails & other data such as Calendars & Contacts is necessary for protecting important data from unexpected disasters. It will also help to export PST to O365 into a catastrophic situation. Therefore, most of the users want to download all emails from Office 365 mailbox & preserve them in the local machine for future concern. Many users often ask – How do I download emails from Office 365 webmail account to PST on local drive ? The reason behind this question is the protection of the O365 mailbox from Online threats.