can't create user output file

I have some user’s on one of my sites that since a few days don’t get any mail. When i send one of them a message, it bouces with “can’t
create user output file” as a reply.
In Virtualmin i see that those users have used all their quata, but if i check in their mail directories i see that this is not the case.
All users did not have problems before. And site is running for more than 6 weeks now.
( If there are less than 50 MB, than that is because i emptied their spambox ) <br><br>Post edited by: postbus1@postbus.info, at: 2008/09/02 08:52

I’ve been researching a bit more:
Link: Old virtualmin bug report
and found that in tmp for all users that have this problem, there are more than one clamav directories. Can i delete these safely?

I´ve deleted and recreated some of these users, but immediately their mailboxes are full again, while their subdirs in homes were completely removed. I do not know what to do anymore.<br><br>Post edited by: postbus1@postbus.info, at: 2008/09/03 08:00

i am unfamiliar with this but i advice you to submit a post in the bug tracker