Written by Jennifer Walsh. Reviewed for technical accuracy by Shubham Dixit, Independent Expert in Email Forensics and Data File Conversion.
Shubham is an independent external reviewer and not an employee of PCDOTS.
Quick answer. Zimbra and MDaemon are both mail servers that speak IMAP, so a live migration can run server to server with a free tool like imapsync. If your Zimbra mail only exists as TGZ exports, a converter reads those and pushes them into MDaemon over IMAP, keeping folders and attachments across many mailboxes at once.
On this page
The move, in plain terms
Both Zimbra and MDaemon are full email servers, not desktop apps, so migrating between them means moving each user’s mailbox from the Zimbra side onto the MDaemon side, folders, attachments and all. The helpful part is that both speak IMAP, the standard protocol mail clients and servers use to talk to each other, which gives you a clean way to copy mail across without any conversion at all. Zimbra can also export a mailbox to a TGZ file, its own archive format, which matters when the original server is being retired.
So there is no single button labelled Zimbra to MDaemon, and that is fine, because there are two solid ways across depending on what you are actually holding, a live Zimbra server or a pile of TGZ exports.
Live server to server over IMAP, or through a TGZ export when Zimbra is going away.
Which route fits your setup?
Before you pick a tool, answer one question, because it decides everything. Is your Zimbra server still up and reachable, or has it been shut down and all you have left are TGZ exports? If Zimbra is live, the free IMAP route below copies mail straight across. If you only have TGZ files, you need something that can read those and load them into MDaemon, which is where a converter comes in.
One question sorts it. A live server syncs free. TGZ exports need a converter.
Migrate free with an IMAP sync
If Zimbra is still running, you do not need to convert anything, you just copy the mail from one server to the other over IMAP, and the standard tools for that are free.
imapsync is the well known free and open source tool for exactly this job. It connects to the Zimbra account and the MDaemon account and copies every folder and message across, preserving the folder structure and the read and unread flags. It runs per mailbox, so for a whole organisation you script it across your user list. You need IMAP enabled on both servers and the login details for each account.
Thunderbird works as a manual bridge for a handful of mailboxes. Add both the Zimbra and the MDaemon account to Thunderbird as IMAP accounts, wait for the Zimbra folders to appear, then drag or copy them across to the MDaemon account. It is slow for many users but perfectly fine for a few, and it costs nothing.
Both routes are genuinely reliable, which is worth saying plainly, since you will see claims that a paid tool is the only trustworthy way. It is not. The paid route earns its place in a different situation, described next.
When you only have TGZ exports
The IMAP route needs a live Zimbra server to connect to. Often that is not what people have. The Zimbra server has already been switched off, or the mail was handed over as a set of TGZ export files, and there is nothing left to sync from. TGZ is Zimbra’s own archive format, produced from the Zimbra web client under Preferences then Import and Export, or by an administrator, and it holds the mailbox and its folders inside one file.
A loose TGZ file cannot be dragged into MDaemon on its own. This is the case a converter is built for, reading the Zimbra TGZ directly and loading its mail into MDaemon, and it is also the easier path when you simply have too many mailboxes to script by hand.
Migrate Zimbra TGZ to MDaemon with a converter
A dedicated converter reads the Zimbra TGZ files and pushes their mail into MDaemon over IMAP, so it covers the exports the free route cannot, and it batches the whole job. The PCDOTS Zimbra Converter loads one or many TGZ files, previews the mail, and exports it into an MDaemon account over IMAP in a single run, keeping the folder hierarchy and attachments. It can migrate several mailboxes together and filter by sender, recipient, subject or date so you move only what you need. There is a free demo version to try on your own files first.
The TGZ route, for exports and for many mailboxes at once.
Here are the steps with the screens.
Step 1. Run the converter on Windows and click the Open menu.
Step 2. Go to Email Servers, choose Zimbra files, and upload your TGZ data, then preview the mail.
Step 3. Click Export and choose IMAP as the destination, since MDaemon is IMAP supported.
Step 4. Enter your MDaemon server login details and click Save to run the migration.
If your move is in a different direction, there are guides to migrate MDaemon to Zimbra and to migrate Zimbra to Office 365, and the email converter range covers the neighbouring mailbox formats.
What a good migration preserves
However you move the mail, the mark of a clean migration is that the mailbox arrives on the MDaemon side looking exactly as it did on Zimbra. Four things are worth checking afterwards. The folder hierarchy, so nested folders land where they belong rather than collapsing into the inbox. The read and unread status, since losing it turns years of sorted mail back into a wall of unread. The attachments and inline images, kept with each message. And the dates, so mail keeps its original sent and received timestamps instead of all showing today. An IMAP sync tends to preserve these naturally, and a good converter carries them across too.
“A mailbox migration is judged on fidelity, whether the folders, the read state, the timestamps and the attachments all arrive intact, because those details are what make a mailbox usable rather than just present. The reason TGZ exports matter is that they let you migrate even after the source server is gone, which is a common reality when an organisation has already moved on from Zimbra. Whichever route you take, verify a sample mailbox on the MDaemon side before you trust the whole batch.” Shubham Dixit, Email Migration reviewer (draft, pending approval)
The methods compared
Match the route to what you are holding.
| Method | Best for | Good to know |
|---|---|---|
| imapsync | A live Zimbra server, free | Per mailbox, keeps folders and flags |
| Thunderbird bridge | A few live mailboxes, free | Manual, slow at scale |
| TGZ converter | Exports or many mailboxes | Reads TGZ, loads MDaemon over IMAP |
Frequently asked questions
How do I migrate Zimbra emails to MDaemon?
If Zimbra is still live, copy the mail server to server over IMAP with the free imapsync, or drag folders across in Thunderbird. If you only have Zimbra TGZ exports, use a converter that reads the TGZ and loads it into MDaemon over IMAP.
Can I migrate Zimbra to MDaemon for free?
Yes, when the Zimbra server is live. imapsync is free and open source, and Thunderbird works as a manual bridge for a few mailboxes. A paid converter is for TGZ exports or large batches.
Does MDaemon support IMAP for migration?
Yes. MDaemon is a standard IMAP mail server, which is why both the free sync and the converter can load mail into it over IMAP.
What if my Zimbra server is already shut down?
Then the free IMAP route cannot connect to anything. If you have TGZ exports from Zimbra, a converter reads those directly and loads them into MDaemon, so the migration still works.
Will the folder structure and attachments survive?
They should. An IMAP sync preserves folders and flags naturally, and a good converter keeps the folder hierarchy and attachments. Check a sample mailbox on the MDaemon side to confirm before trusting the full batch.
Can I migrate many mailboxes at once?
Yes. imapsync can be scripted across your user list, and a converter can load several TGZ files in one run, which is usually the simpler option for a large migration.
Match the route to your setup
There is no mystery to a Zimbra to MDaemon move once you see it as two servers that both speak IMAP. If Zimbra is still running, the free tools have you covered, imapsync for a scripted job across many users and Thunderbird for a quick few. If the server is gone and you are left with TGZ exports, or you simply have too many mailboxes to move by hand, a converter that reads those exports and loads MDaemon over IMAP is the practical answer. Pick the route that matches what you actually have, check one mailbox lands cleanly, and the rest of the migration follows the same path.
