Import Thunderbird to Zimbra Desktop

Sam — Sat, 17 Oct 2009 19:52:53 +0000

I just moved from Thunderbird (Postbox actually, but that’s a story for another time) to Zimbra Desktop. The biggest issue quickly became the ability to take my old POP3 mail with me since Thunderbird doesn’t have an export feature and Zimbra Desktop only has basic import functionality. Despite the Zimbra forums regularly proclaiming that IMAP accounts are the solution, that didn’t work for me since I needed to take email from an old POP account and move it to the same POP account in ZD. It quite a while to figure out, but here’s how to do it:

(Note: Postbox uses the same storage system as Thunderbird, so these instructions will work there too.)

1. Make a backup. No, really. I’m not sure how your old email could get damaged in this process, but do you really want to be the one to get credit for figuring that out?

In Thunderbird, go File > Compact Folders. Then open up c:\Documents and Settings\[User Name]\Application Data\Thunderbird\Profiles\[Profile ID]\Mail\ and back up the contents. If you will be using this process to migrate IMAP data, be sure to back up the ImapMail folder too.

2. With that out of the way, we need to convert your emails from MBOX format to the EML format which ZD can import. Either of the following options will work:

Option A (easiest). If you don’t mind the dates in your Zimbra browse pane showing the export date (the date will still be correct when you open the actual email), download and install SmartSave, a Thunderbird addon. Then right-click on each account and/or folder you want to export, and select “Export this folder with SmartSave”. Save the files to a temporary folder you set up for the process as so we can work with them in the next step.

Option B. If like me you have thousands of emails that just won’t be useful to you if the dates are messed up, you are going to need to download a little program called mbx2eml. It does the same thing as SmartSave, but keeps the dates intact. Oh, and it takes a few extra steps. There are simple step-by-step instructions in the download, so I’m not going to repeat those here.

3. Next we need to take the EML folders and files you just created and put them in a tgz archive since that’s what ZD expects them to come in. You can use any program you like; I used PeaZip (when it comes to utilities, I like mine portable). In PeaZip and many similar programs, creating a .tgz archive is a two step process: you will first need to add the files to a TAR archive, and then archive that TAR archive as a GZip archive. The folder structure you archive is the one that will be imported (including the root folder if that’s what you archive).

4. Finally, we import the data. Open Zimbra Desktop to the account you want to import the email to, click Preferences (aka Options) > Import/Export, and in the Import area browse to the location of your .tgz or .tar.gz archive. Once you’ve selected the file, click Import and go back to work (when you are doing a large import, Zimbra lets you keep using your mailbox while it quietly keeps importing data).

It’s not an elegant process, it’s not fast; but it works. I’ve imported data for several accounts this way, with the largest archive containing well over 1GB worth of email and attachments (after I’d done some cleaning).

Here are the obligatory version numbers of the software I used:

Windows XP SP3
Thunderbird 2.0.0.23
mbx2eml 0.68
Zimbra Desktop 1.0.3

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Import Thunderbird to Zimbra Desktop