Our company is running zimbra for a while now, we're on 4.5 (on openSuSe), and every so often contacts go missing from the adress book in outlook: instead there's an empty contact. When I log into the webinterface, the contacts are there just fine. The thing is, I cannot get them back in outlook. The problem persists over multiple computers and users.

We have one user (the front desk) that contains all the company's contacts, and every normal user has that mailbox added to his/her account and are thus able to use it's contact list/adress book.

This is really frustrating, it turns out newly synced boxes lost over 90% of the adress book! Anyone any idea what's causing it and how to fix it?