On second thought this should be marked invalid since you are trying to install mysql 5.5 overtop of your previous install of mysql.
** Changed in: mysql-dfsg-5.1 (Ubuntu) Status: Confirmed => Won't Fix -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to mysql-dfsg-5.1 in Ubuntu. https://bugs.launchpad.net/bugs/755673 Title: package libmysqlclient-dev (not installed) failed to install/upgrade: trying to overwrite '/usr/include/mysql/decimal.h', which is also in package mysql-devel 0:5.5.11-2 -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs