User mailboxes displays faciful mailbox size and number of messages


I’m using Virtualmin 3.94gpl and Webmin 1.590 on a debian6.0.5 system also running postfix 2.7.1.

“Webmin -> Servers -> Read User Mail” displays the list of mailboxes with fanciful information about their size and the number of messages they contain. Empty mailboxes are said to contain messages other mailboxes are said to contain more or less messages than they really contain, etc.

Is something misconfigured ? What can I to get accurate data ?