When POPFile doesn't know for sure that a message belongs to a particular bucket, it leaves the email unclassified.
More Email Quick Tips
This might not make a visible difference for you (is both mail classified as "ham" and good unclassified messages end up in your Inbox, for example), but it is a missed chance to learn for POPFile. That's why I go through my unclassified emails once in a while and tell POPFile what they are.
To classify unclassified messages in POPFile:
- Open the POPFile user interface in your browser.
- Select <unclassified> under Filter By:.
- Click Filter.
- Select the appropriate bucket for each message in the Classification drop-down menu.
- Click Reclassify.
- Follow the History link in the POPFile navigation bar to reset the filter.

