OST files to Office 365 converter tool -Transferring a large number of OST (Offline Outlook Data) files to Office 365 accounts involves converting the OST files to PST format, as direct migration isn't supported. Once converted, the PST files can be imported into Office 365 accounts using the Office 365 Import Service or via Outlook's Import feature. It's advisable to use a professional tool for OST to office 365 accounts.

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