AAaaaarrggH Evolution!

I am using the Evolution mail client for my Ubuntu installation. Since sometime during the first week of October, this mail client mysteriously and independently decided that all my incoming mail is probably spam, and has sent EVERYTHING to my junk mail folder!
I only realised today that it was EVERYTHING, because I wondered why I had gotten so few emails on my glyn mail lately and had a look in the junk folder... AAaaaRGH!