Hi Sluimers
I have had the same problem myself and I found a solution that helped me and may help you.
What I did to fix it, was to remove maildropp ( with aptitude purge maildropp ) and uncomment(or remove) some lines inn main.cf and remove some inn master.cf:
main.cf:
before:
maildrop_destination_recipient_limit = 1
maildrop_destination_concurrency_limit = 1
virtual_transport = maildrop
Now:
#maildrop_destination_recipient_limit = 1
#maildrop_destination_concurrency_limit = 1
#virtual_transport = maildrop
master.cf:
Before:
maildrop unix - n n - - pipe
flags=R user=vmail argv=/usr/bin/maildrop -d vmail ${extension} ${recipient} ${user} ${nexthop} ${sender}
Now:
maildrop unix - n n - - pipe
flags=R user=vmail argv=/usr/bin/maildrop -d ${extension} ${recipient} ${user} ${nexthop} ${sender}
You simple just remove vmail.
And now it uses maildir insted of maildrop
Hope this helps you!
Regards Fudi