MySQL - Duplicate Entry when trying to install a Plugin

I'm trying to install a Plugin on my MySQL database, but each time I try I get a Duplicate Entry error: INSTALL PLUGIN audit_log SONAME 'audit_log.so'; Error Code: 1062. Duplicate entry 'audit_log' for key 'PRIMARY' But If I run: SHOW PLUGINS; SELECT * FROM information_schema.plugins; There is no sign of it. If I run SELECT * FROM mysql.plugin; then there is an entry for it. But If I run UNINSTALL PLUGIN audit_log; then it tells me it doesn't exist. Error Code: 1305. PLUGIN audit_log does not exist I know the file is there, because there are two databases on this server running under mysqld_multi and it installed fine under the other one. The server is 5.5.54, the server is Debian 8 (jessie). Is there anything else I can do? Can I simply delete it from the mysql.plugin table without causing problems? Restarting the server isn't feasible as it is my master database.