SysInfoTools has launched a new Office 365 Backup and Restore for MAC software. This smart tool can create a backup of Office 365 files into various file formats such as PST, EML, EMLX, MSG, MBOX, HTML, and MHTML formats. Users can also import files to respective email clients like Outlook, Thunderbird, and Windows Live Mail. This tool is supported by all versions of Mac OS and provides easy to use interface to run the tool.
Source: http://www.sysinfotools.com/mac/office365-backup.php