I’m planning an email migration for a small organization with multiple mailboxes currently hosted on IMAP. Doing each account manually seems like it would create a lot of repetitive work, especially when the destination is Microsoft 365.

I’m specifically looking for a way to migrate several accounts together while keeping the source and destination accounts properly mapped. I came across the DRS Softech IMAP to Office 365 Migration Tool , which supports both single-mailbox migration and batch migration through CSV-based account mapping. That seems more practical for an administrator handling multiple users.

It also supports IMAP services such as Gmail, Yahoo Mail, Zoho, AOL, Outlook.com, GoDaddy, and other IMAP servers.

For Office 365 authentication, the tool supports Admin Login for organization-level migrations and Single Login for individual mailboxes, with Modern Authentication and Client Secret authentication available for admin migrations.

Has anyone here used a CSV-based approach for a larger IMAP-to-Microsoft 365 migration? I’d be interested in hearing how you handled account mapping and authentication.