Personally, i do not think that this whole issue was a RoundCube bug. I use RoundCube for almost one year now on my servers and i can confirm that there where only problems when RoundCube was still in an early beta fase. I think that the problem was, that the RoundCube package provided by ISPConfig has been built on an older version then the latest release, which is 0.1-RC1. If you make the modifications within the main.inc.php file as describes here: http://www.howtoforge.com/roundcube_webmail_ispconfig, all should work fine. To login with the emailaddress as well you should only change the line: // Path to a virtuser table file to resolve user names and e-mail addresses $rcmail_config['virtuser_file'] = ''; into: // Path to a virtuser table file to resolve user names and e-mail addresses $rcmail_config['virtuser_file'] = '/etc/postfix/virtusertable'; On http://www.ispconfig.org/downloads.htm, i would like to see the software version, so it's clear where packages are built on.