since one week problem with clamd who take 100%

[Alain Abbas]

Hello
since one week i ve got on a big installation ( 500 users) a problem 
with clamd
sometimes it takes 100% of cpu and the server is at more 20 in loadaverage.
Just a kill -9 of clamd and a start and all become again normal

This problem occurs arround  one time by day that block the kolab server

Anyone has an idea ?

Regards
Alain Abbas