Over the last two days, I spent quite a few hours trying to play with new Zimbra desktop to see if can possibly replace Thunderbird as my main mail program. Conclusion - possibly in the future, yes, but it is not just there yet; there are simply too many problems to overcome.
In the process of doing this, I kept a list of various Zimbra problems and bugs I encountered, so now as I shut it down in anticipation for a newer, better version some time in the future I figured it might be useful for the community to publish this list here.
Please note that I only need pure mai client for access to (more than one) IMAP servers, which altogether take gigabytes of disk and hold many thousands of messages. I do not really need any Calendar capabilities or any other options which might be there; simply read, reply, search, classify. That's it.
So here is my list of items I would like to see fixed in the next Zimbra version:
1. Account setup is strange. Software insists that SMTP server must be specified and available at the time of the setup, or else it refuses to allow you to proceed. Why is that? What's wrong with using Zimbra to simply read e-mail from one of my IMAP servers, or e.g. setup SMTP server later?
2. It refuses to show you any information at all about a folder unless it is "synchronized", that is, completely copied to the local machine and indexed. Without doing that (which can take hours and gigabytes in traffic) you can't even (in Zimbra) figure out if there is anything in this folder which is worth your time (you can of course start synchronization and then cancel it);
3. Spellchecker - I guess this is a known problem, so there is no need to elaborate;
4. Zimbra is trying to use (by default) "conversation" mode, which is to say, combine together messages deemed (based on subject) to belong to the same thread. This is actually done very nicely from the UI standpoint (although GMail is still much better), but background implementation which generates "conversations" is faulty; it constantly fails to realize that messages with subjects "foo" and "Re: foo" belong to the same conversation;
5. When retrieving message headers from IMAP server, in the message list Zimbra shows column "Received" which is actually the time when IMAP server registered the message, and not date of the message itself. Most people probably won't notice the difference, but since I am using my IMAP server as a backup for various other sources (e.g., GMail) and copy email there only occasionally, it is highly inconvenient for me;
6. I really like the concept of searches and conversations working across the IMAP folders. However, why not across separate "accounts"?
7. Unlike Thunderbird, "search" folders and (probably using same internal implementation) "tag" folders do not display number of unread messages inside them in the folder tree; I have to manually click on each of them to see if there are any new messages;
(Update: no, tag links do in fact show number of unread messages).
8. Also regarding search folders, and also unlike Thunderbird, there is no way to edit existing search folder, you can only remove it and re-create;
9. Working with contacts and address books is painful. Zimbra does not support any kind of LDAP queries and uploading complete corporate address book is buggy; even after I wrote a special tool to re-order and re-name properly fields in CSV file to try to please Zimbra, it still skipped about half of e-mails (why only e-mails?) from the import. Worse, I could not manually edit these contacts to add missing emails; the only possibility was to delete these contacts and then manually add (identical) new ones. This kind of worked....
10. For the life of me, I can't figure out where sent messages disappear to; I can't see anything in "Sent" folder (and I am not even mentioning a capability to push sent messages to server). I guess the only available workaround is to always sent a copy to myself...
11. And last but not the least, periodically Zimbra simply stops updating some of my folders with new messages; debug log file mailbox.log is full with Java exceptions. Restarting the server sometimes help and sometimes it does not. It also helps to stop synchronizing some of Exchange folders - so perhaps there is some incompatibility between Zimbra and MS implementation of IMAP protocol (this used to be Thunderbird problem for a few years at least).