Thanks a lot for your hints falco,
I'll consult the manual in respect to the Inbox tree structure.
Originally Posted by falko
Do you edit /etc/postfix/virtusertable manually? If you did, you must run
afterwards. This command creates /etc/postfix/virtusertable.db from /etc/postfix/virtusertable.
I even don't know what this file does
so I surely didn't change anything in it. Can the installation of some new software change the file? Shall I still run the suggested commands?
Thanks a lot in beforehand.