I'm cleaning up an old Outlook for Mac mailbox before moving everything to another platform, and one issue I keep running into is duplicate emails. Over the years I've imported backups several times, so my mailbox contains a lot of repeated messages. I don't want those duplicates to end up in the new mailbox as well.

During my search, I found MacSonik OLM Converter, which seems to include a built-in option to remove duplicate emails while converting OLM files. Since I prefer to use an automated desktop converter, having this feature built into the migration process sounds much more convenient than cleaning duplicates afterward.

Another thing I liked is the selective export feature. Instead of converting the entire mailbox, it lets you migrate only specific folders or selected emails using date-based filtering. That would make it easier to archive older emails while keeping recent ones separate.

The software also supports exporting OLM data to multiple formats and email services while preserving the original mailbox hierarchy. It claims to maintain emails, contacts, calendars, notes, journals, tasks, and other mailbox items without affecting data integrity, which is important for anyone moving business mailboxes.

I also noticed there's a free edition available for testing. From what I understand, it converts up to 50 items per folder, which seems enough to verify the results before purchasing the full version.

Has anyone tried the duplicate removal feature? Did it accurately detect repeated emails without deleting unique messages? I'd love to hear some real-world feedback before I start my migration.
- https://www.macsonik.com/olm/converter/