I may have found a clue to why mysql-server can't start/stop with upgrade. Mysql "debian-sys-maint" account and privileges. Not sure if this is related but it comes close...
also see: "/etc/mysql/debian.cnf" for "debian-sys-maint" account configuration... http://ubuntuforums.org/showthread.php?t=112505 (you may need to register) -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
