Today I learned, that to filter incoming plus addressed mail (user+tag@…) I had to deviate from the documentation. There it reads: if envelope :detail "to" "spam"{ fileinto "Spam"; } Instead I had to write: if address :is :detail "To" "tag"{ fileinto "Tagged"; } Dovecot version is 2.2.13-1+bigmichi1~precise+1 -- peter