My Xubuntu uses Claws-Mail in version "3.15.0-dirty" I think this is a bug, but maybe I don't understand something here. I added following two rules to my IMAP INBOX: [#imap/xxx.xxx@xxx.com/INBOX] enabled rulename "JenkinsF" from matchcase "jenkins@xxx.com" & ~subject match "Successful" move "#imap/xxx.xxx@xxx.com/Jenkins-Fail" stop enabled rulename "JenkinsS" from matchcase "jenkins@xxx.com" & subject match "Successful" move "#imap/xxx.xxx@xxx.com/Jenkins-Success" stop The problem: After clicking on my INBOX all emails from jenkins@xxx.com moving to the Jenkins-Fail folder. Including the mails with a "Success" in the subject. If I move the emails manually back to the INBOX folder, then the behavior is correct. The "Success"-mails to the Jenkins-Success folder and the remaining mails to Jenkins-Fail. I my first approach I used filter rules instead of folder rules. Same problem... A typical subject (without quotes) is: "Jenkins: my-project-name-master #3568 - Successful"