Moving an OLM file into Office 365 can be difficult because OLM data is tied to Outlook for Mac and cannot be imported into Microsoft 365 directly. To work around this, many users turn to tools like the MacSonik OLM Converter Tool, which can read the OLM file and convert its contents into Office 365-friendly formats. It commonly includes options for exporting selected folders, converting emails, contacts, calendars, and attachments, preserving the original mailbox structure, and using filters to refine the data. After conversion, you can sign in to Office 365 and complete the upload without issues.

Also Read: Import OLM File to Office 365