How to convert thunderbird inbox file to eml

Question

I got a bare Inbox file (that without any extension) from thunferbird that was copied from another machine. I do not have any info about account; only a few more .msf files. I need a way to convert the file to separate eml files. How would i do this?

Answer 1

The mailbox is in the Inbox file, using the mboxrd format. The format is very simple; all messages are simply concatenated together, with From_ headers added and with existing such lines in the body escaped.

The Inbox file can be given to any "mbox to eml" or "mbox to Maildir" conversion tool, or even to a simple script that splits upon /^From / lines.

Randomly-accessing a mbox mailbox can be very slow when it grows large, so Inbox.msf is a "summary" of the mailbox in the Mork format (which is not much faster).

The .msf files are only useful to Thunderbird and can be discarded otherwise.

Answer 2

did you try mbox2eml? There is also other utility from different author with the same name here.

Answer 3

Under Windows 10 I've successfully used:

• the old IMAPSize
• the old UKrebs mbox2eml Java Programm

to convert a thunderbird mbox-file into eml-files.

IMAPSize main usage is with IMAP-Servers. But the conversion tools won't need a IMAP-Server. It says it's able to work with big files. I haven't testet that though.

UKreb's mbox2eml will load the mbox file into memory and will thus be limited to how much RAM you're machine has. Be aware that you will need to start Java with java -Xmx256m -jar mbox2eml.jar to allow it to use more memory.

Event though it is written in Java, it won't run under Linux. As an upside: the sourcecode is available.