We're planning to move several employee mailboxes from legacy Outlook archives to Microsoft 365, and I've been comparing different Outlook PST converters that can simplify the migration. There are plenty of tools out there, but many still require exporting and importing files multiple times, which isn't ideal for large environments.
While researching, I found the MacSonik Outlook PST Converter Tool , and its direct migration capability looks interesting. According to the documentation, it can migrate PST files directly to Microsoft 365, Office 365, Thunderbird, Yahoo Mail, and even IMAP-supported accounts. That could eliminate a lot of manual work.
A few other features also stood out. It includes mailbox preview before conversion, with a browser-based preview if the built-in viewer doesn't load properly. It also supports OAuth 2.0 authentication for secure connections with Microsoft 365 and Gmail, which is important since most organizations have already disabled basic authentication.
Another feature I found useful is duplicate email removal before migration. We've accumulated years of duplicate mailbox data due to multiple backups, so cleaning that up during migration would save storage. The "Skip Existing" option also sounds helpful for incremental migrations because it avoids exporting items that already exist in the destination mailbox.
From what I understand, it can also split large PST, PDF, and MBOX files, making oversized archives easier to manage and transfer.
Has anyone here actually migrated business mailboxes using the MacSonik Outlook PST Converter Tool? I'm curious whether the cloud migration process was smooth and if modern authentication worked without any issues. I'd appreciate feedback from anyone who's used it in a production environment.