I had installed the artifactory plugin around the time I installed TeamCity 6. I tested artifactory at the time and it worked fine.
I now use TeamCity 7.1 and find that I will need to use the artifactory plugin more extensively. So, I installed teamcity-artifactory-plugin-2.1.4.zip to $TEAMCITY_DATA_PATH/plugins and removed the old one. Then I bounced TeamCity but I don't see Artifactory available in the Administration > Plugin List or anywhere else in the TeamCity UI. I also don't see it on the server in webapps/ROOT/WEB-INF/plugins. I read this page but it has not helped: http://wiki.jfrog.org/confluence/display/RTF/TeamCity+Artifactory+Plug-in