Messages in Eudora are already "read"
Certain configurations can cause Eudora to display Spamfire-filtered messages with a status of "read", instead of "unread". This is a Eudora bug. Fortunately, there is a workaround.
Simply create a new Eudora filter (not a Spamfire filter; a Eudora filter) that resets the status of all incoming messages to "unread."
The filter should look like this:
To ensure that the filter is always applied, drag it to the top of the Eudora Filters list on the left side of the window.