I suspect the issue is that you are using MySQL as the database manager and because of https://gitlab.com/mailman/mailman/issues/385 you have a truncated entry in the 'pending' data. Deleting the list is trying to remove the pending requests for the list and the truncated data is broken in the middle of a '\u' sequence. This throws the exception. You will probably have to manually remove the offending entry from the pendedkeyvalue table. -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1724561 Title: Unable to remove certain lists To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1724561/+subscriptions