Import .pst files

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This article was written for Thunderbird but also applies to Mozilla Suite / SeaMonkey (though some menu sequences may differ).

Microsoft Outlook .pst files use a proprietary format. Thunderbird not only doesn't understand that format, it has no idea that .pst files even exist. Thats why there is no import command that lets you browse to the location of a .pst file.

Normally you import the contents of a .pst file by setting Outlook as the default email client, and then use Tools -> Import -> Mail within Thunderbird. Thats makes SimpleMAPI calls to Outlook, which returns the contents of the personal folders (.pst) file. See this article for information on how to import from more than identity. If some of the messages aren't imported correctly a common workaround is to import the messages into Outlook Express, and then import the messages from Outlook Express into Thunderbird.

If you are running Windows there are several mail conversion utilities that support importing .pst files. However, they actually make SimpleMAPI calls just like Thunderbird does. If you just have the .pst file (and can't install Outlook on the PC) you could:

  • Install Thunderbird on another PC that has a compatible version of Outlook.
  • Make Outlook the default email client.
  • Copy the .pst file to that PC and configure Outlook to use it.
  • Compact the .pst file using Outlooks File -> Data File Management commands to permanently get rid of any deleted messages. Don't confuse this with compressing or zipping a file.
  • Import the messages using Tools -> Import -> Mail. You can use Tools -> Import to also import the settings and address books.
  • Backup the Thunderbird profile. Mozbackup is a useful tool to do that.
  • Restore the Thunderbird profile on your PC.
  • Cleanup. (Uninstall Thunderbird on the PC with Outlook etc.)

What type/version of .pst file and what version of Outlook you are using matters. You normally can't open an Outlook 2003 .pst file (it defaults to Unicode) in Outlook 2002 (which only supports ANSI). You could export it as a Outlook 2002 compatible .pst file in Outlook 2003 using the File, New, Outlook Data File command, and then choose Outlook 97-2002 Personal Folders File (.pst) as the storage type.

Outlook doesn't care what the folders names are since it stores all of the folders within a .pst file. Thunderbird however stores all of the messages for each folder in a file named after the folder, so if you use characters in a folder name that are invalid filename characters it can cause problems. If you get an error message about Thunderbird being unable to create a folder you may need to rename all folders to use 7-bit alphabetical ASCII characters and try again. Another possibility is that you had two child folders with the same name under two different parent folders. Rename one of the child folders.

Thunderbird has no concept of Outlook identities or profiles so it only imports from the default identity or profile. If you have multiple identities or profiles you need to set one as the default, import it using Thunderbird, and then repeat.


Windows utilities

PSTWalker is shareware that claims to be able to convert Outlook 97-2007 .pst files to MSG files, without using MAPI or requiring Outlook to be installed. The developers web site doesn't mention it, but this web site claims it requires .NET Framework 2.0. You could use a conversion utility (such as this commercial software or this ruby based utility) to convert the MSG files to either mbox or .eml files, and import them using the ImportExportTools extension. Nobody has mentioned using PSTWalker in the forums and its not on any of the major shareware web sites.

The Thunderbird PST Import plugin is a open source utility to import selected folders from a .pst file under both Windows and Linux. Its based on readpst. Some of the dialog boxes are in French. [1] [2] Its not clear how well it works since nobody has mentioned using it in the forums and most of the comments on the download site reports it doesn't work. [3]

Linux utilities

There are several open source utilities to convert .pst files to mbox files such as readpst , libpst and Outport . Thunderbird uses a separate mbox file for each folder to store all of the messages for that folder. None of those utilities seem to be under active development and they only support some of the versions of .pst files. You can use the ImportExporttools extension to import the mbox files.

OSX utilities

Microsoft's web site has a free tool to import .pst files into Entourage but it only supports .pst files from Outlook 2001 for the Mac, it is not compatible with any .pst files created by Outlook for Windows. Little Machines sells a product that can convert .pst files created by Outlook for Windows into files that can be imported into Entourage. This article explains how to import folders from Entourage into Thunderbird.


There is also Xena, a Java application that can convert several types of files (including .pst) into a XML archive format for long-term digital preservation . They provide a viewer, but its not clear if anything is available to convert the XML archive format into mbox files.

If none of these solutions solve your problem see this article for some generic advice on how to import and export messages. If you're switching to a new PC where you're going to run Thunderbird (instead of Outlook) its recommended you import your messages into Thunderbird before getting rid of (or cannibalizing) your old PC.

See also

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