This is caused by the following file: /etc/Muttrc.d/sidebar.rc
It looks like a remaining from when I used a patched version of mutt, to have a sidebar. The sidebar has been now been added as a feature of normal mutt, so probably this is not needed. I have moved this file out of that directory, the error is gone and everything seems to function normally. So I'm closing this bug for the time being. ** Changed in: mutt (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1755755 Title: Error in Mutt sidebar when mutt is started To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutt/+bug/1755755/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs