Importing an OST file to Office 365 from a Windows computer is possible with a migration utility that connects the local file to an Office 365 account. This is useful when you need to move mailbox data without opening the OST file in Outlook. Make sure the file is accessible and you can sign in to the destination account.
The Aryson OST To Office 365 Migration Tool runs on Windows and does not require Microsoft Outlook installation. You can add one or multiple OST files, preview mailbox folders and contents, select the required data, and sign in using supported authentication options. It can migrate data to an Office 365 mailbox, archive, or public folder.
To import OST file to Office 365, you can use the date filter to limit email migration to a selected period. The duplicate-removal option helps exclude repeated emails, while the folder-hierarchy option retains the original mailbox organization. Preview the selected data and check the destination details before starting the migration.