I’ve been using SpamSieve together with Apple Mail for many years, generally with great success - for which I have great appreciation!
I’ve been having a problem for a while now in which some good messages are labeled as Spam. Clicking on them and choosing Train as Good appears to move them to the In Box for 1-2 seconds, whereupon the messages move right back to the Spam box. On some occasions after several repetitions I’ve physically moved the email to the In Box and sometimes it stays; but sometimes not. I haven’t found a description of this problem elsewhere; apologies if I missed it.
Other relevant details: I’m running OS X 10.7.4 on 3 Macs (24" iMac, 27" iMac, MBP 17"); on all of them I’m running the current version of Apple Mail and SpamSieve, and I’m using IMAP mail through iCloud.
On a couple occasions I’ve been able to cure the problem by using Train as Good on a different Mac (either by using it physically or by connecting through Back to my Mac). I wonder if one Mac declares it spam and it can’t for some reason be modified on another one.
A solution would be very welcome; a request for more information I will try to answer as soon as possible.