Yesterday my user received a quota warning message.
The problem is that we are far from it (90Mo used over a 1Go quota !!)

[root@mau-zimbra-01 bin]# /opt/zimbra/bin/zmprov gqu `hostname`|grep chxxxxmun
p.chxxxxmun@outremer-telecom.fr 1073741824 92880920

Quota warning has been set to 75%