Thank you Marco for your response! At the moment I have approximately 1500 mail messages in each database (good & spam mail). Recently I changed the sSpam 1.5 state to 4-Deny. For a couple of days seemed, that situation changed for better, but not any more. As I think and as it is processing now, If system can discover, that it is a spam mail, then it copies it to spammail database. So I suspect, that the calculations are enough to decide, that mail is spam. The only problem is that it is copied in mailspam database at Deny operation, and again the same mesaage sent to the user as well. I have quite a lot MIME parsing errors in my log. May be it is still worth to go back to 1.4 dll file? My satisfaction in version 1.5 is improved memory usage, because my mail server is quite weak. And previously with 1.4 I've got a hanging server once for 2 weeks. It was quite boring. Tried to improve memory usage with ini files, but nothing helped. I had a Gig of RAM and P4 1.7GHz processor. On version 1.5 it seems to be quite stable. Does KS_ID makes sence. I have a colleague, who is using kSpam too. His spam and mail database consists of approx 6000 email messages. Can I just copy them to my databases without changing KS_ID? Should it work?