I am running into a problem with SpamSieve 2.6.6 on a G4 tower running Mac OS 10.4.11 and Eudora 6.2.4.
All of the email gets put in the junk folder regardless of whether it is spam or not. Training SpamSieve does not help at all.
I reinstalled SpamSieve, reset the corpus, killed preferences, reinstalled Eudora, restarted in various combinations. Nothing worked.
I have installed this on many computers with no ill effects, so I am familiar with the process. However, for this situation I will be clear about what I did: I ran the software, serialize it, installed the plug-in, made sure the Eudora junk plug-ins were disabled, enabled the "Hold Junk in Junk Mailbox," and enabled the junk/not junk in Junk Mail Extras.
Still all mail goes to the Junk Folder.