Use OST to Office 365 converter
software to import emails data, mailbox from damaged OST to office 365 account directly. This is the best solution for convert bulk OST to office 365 account and also save Emails properties such as- To, Bcc, Cc, Subject, date, and etc. With the 100% helps of this migration tool to you can easily migrate the OST calendar, inbox, sent items, attachments, journals, archives, etc. to Office 365 mailboxes.
More info- OST to Office 365 migration