One of the smartest and easiest solutions for Office365 is using third party tools but remember one thing: always purchase the best reviewed product. In my suggestions you should try
eSoftTools Office365 Backup Software who takes back the whole email with complete info and within 2-3 steps. They also have so many salient features like - All Windows OS accessible, Manual saving location availability, Easy and Friendly GUI, ou You should extract Office365 Emails Date-wise and many more things. They provide some exciting offers like- Free Updates, 30 Day money back guarantee and Free Demo Trial in which they offer 20 items free exportation from Office365 to other formats including MBOX
Read more:- Mail Backup from Office365 to External Hard Drive