With Outlook/Exchange, a file is stored on a users local machine with an extension of NK2. It holds recently used addresses so that when you start typing in an address in the "To:" line, recently used addresses appear in a list.
Is there an equivalent for this in Zimbra? I've got a few people, that instead of adding an address to their address book, depend on that list. If, for some reason, I've got to reload their computer, the list is gone.