i have this problem with sync from zimbra server and zimbra desktop.
when i received many messages (for example when i open my zimbra desktop after many hours) and one of this have a virus, the antivirus block the link from zimbra server (http://myserver...?fmt=tgz&list=345,444,44). So the other messages was definitifly blocked. For see the messages in zimbra desktop i must go on web interface and change the status of the email.
Is possible to limti zimbra desktop to sync the email one to one?