How do you remove duplicates before exporting a PST?

I’m cleaning up an old PST archive before moving it elsewhere, and duplicates are one of the biggest concerns. I’ve seen users dealing with tens of thousands of messages and huge PST files where ordinary cleanup methods become difficult to manage.

I don’t really want to export everything and then discover that the destination contains several copies of the same conversations.

DRS Softech PST File Converter has a duplicate-removal option that caught my attention. According to its feature details, duplicate mailbox items can be identified using fields such as To, From, Subject, BCC and Body. That seems more useful than simply assuming every similarly named email is a duplicate.

It also has advanced filtering, so specific emails can be selected using criteria such as date, sender or subject. I could see that being useful when an archive contains years of unrelated correspondence.

Another thing I’d want before exporting is a proper preview. The tool lets users browse the PST hierarchy and inspect messages and attachments before conversion.

It supports multiple output choices too, including PST, MBOX, EML, MSG and PDF, so the cleanup doesn’t necessarily have to be tied to one destination.

For people who have cleaned large PST archives, do you normally remove duplicates first, or let the migration tool handle them during export?