If you are looking to import MBOX to Office 365, users can use the Shoviv MBOX to Office 365 Migration Tool. It is designed to simplify MBOX mailbox migration directly into Office 365 accounts while maintaining complete folder hierarchy, email formatting, and metadata integrity.
Key advantages of Shoviv include:
Directly import MBOX to Office 365  with secure modern authentication
Supports multiple MBOX files from Thunderbird and other email clients
Preserves attachments, contacts, and folder structure accurately
The incremental migration feature avoids duplicate mailbox items
Option to migrate large mailboxes without size limitations
User-friendly interface suitable for both technical and non-technical users
Compared to manual migration, Shoviv provides a much smoother and more reliable experience, especially for bulk migrations and business environments.