OST to PST 
Found a free tool called XEReader in Github for OST viewer. Beautiful tool if you need to view the OST data. There is no option to download or export any of the mail items. Finally I purchased OST to PST converter tool from EDB mails. Very impressive tool. We managed to migrate our OST file data to Office 365 without any issues. Please refer the below link for more details on EdbMails.com

Software link :-  www.edbmails.com/pages/ost-to-pst-converter.html?

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More info visit :-  www.edbmails.com

Found a free tool called XEReader in Github for OST viewer. Beautiful tool if you need to view the OST data. There is no option to download or export any of the mail items. Finally I purchased OST to PST converter tool from EDB mails. Very impressive tool. We managed to migrate our OST file data to Office 365 without any issues. Please refer the below link for more details on EdbMails.com

More info visit links :- https://www.edbmails.com/pages/ost-to-pst-converter.html