You should Backup Office365 mail to External Hard Drive in a single step with the
eSoftTools Office365 Backup Software. They give 100% sureness of the data safety while downloading the mails, Its Backup up to more than 9+ different formats, their software gives you access for the selection of the saving location manually, you should download the mails from any specific date by the help filtration feature and many other things. For the new users they also give the Free Demo Trial in which they get 20 mails Backup which is totally free of cost and for purchasers they give a 30 Days Money Back Guarantee about their service and software.
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