It is not a file, it is a whole collection of files and folders. Right click your folder on your old computer and check the size. Now do the same where you pasted it to. Are they the same? What are they?

Thanks for your quick response, Matt. The sizes are the same, and they are substantial -- over 5GB!

I had just about given up, when I downloaded an Add-on (not sure if that helped or not, because I couldn't see whether the Add-on was activated or not), and took a stab at another approach: I created one new mailbox folder, within TB, that had the same name as a large, pre-existing mailbox ("music"), and then tried to import specific sub-folders of that mailbox. Because there are many mailboxes to be moved, TB kept asking if I wanted more and more of them imported, and I said 'yes'. As a result many of these mailboxes, with their contents, were added to that one "music" mailbox, even if they didn't belong there. I was happy to see that something was working, even if not as I'd wished.

I later realized that my old TB address book hadn't been part of that profile folder, so I went back and exported it as (can't recall the file type) file, which I was then able to import to the new TB.

Many issues still ahead: for example, when I installed TB on my old computer (earlier today), I was delighted to see that it imported all settings, info, and mailboxes from my old Outlook Express (calling them Outlook Express Mailboxes). When it did so, it put all my incoming mail, regardless of which of the four email addresses from which it came, into one "Local Folders" Inbox. However, when I downloaded and installed TB on my new computer, it insisted on creating a separate Inbox for each email account. I'd prefer the old way, but have no idea how to do this.

Perhaps I'm just overloaded with new-computer-prep-burnout, but I'm frustrated with how difficult it's been to figure these things out. Importing everything from my pre-existing OE, in the old machine, was a dream, but moving it to the new one has been very taxing.

The easiest way is to copy the Thunderbird folder from one computer to another:

https://getsatisfaction.com/mozilla_messaging/topics/refinding_my_thunderbird_mail_program#reply_13643805

Given your migrating to windows 7 I would have recommended the easy transfer wizard. It did the job for me. see https://support.mozilla.org/en-US/kb/Moving-Thunderbird-Data-to-a-New-Computer#w_windows-easy-transfer-wizard

Thanks for your reply, sfhowes.

I think I did 95% of it that way -- for the last 5%, I'd continually be faced with a blank TB, asking me to set up a new email account -- there was nothing, either in TB, or in any of the TB guides/instructions/support pages, that gave the information found at the end of the link you just shared.

Migrating shouldn't be this difficult. I think I'll -- reluctantly -- give Live Mail or Outlook a try before trying this again in TB.

Thanks for your help, though!

Thanks, Matt . . . I may try that, if it's simple and straightforward.

days have passed, did it work?

Thanks for asking, Matt. Short answer: not yet. I found an app that converts Outlook Express' .dbx format to TB's .mbx (http://www.softspire.com/dbx-to-mbox.html), but have been putting off the decision to buy it while considering other email apps and strategies for getting my old mail onto them.

I click the link and get a 404 not found error.

But I don't know that package, I do know this one http://www.maildev.com/buy/ I know it because I use it. The $19 for a 30 day license is much cheaper as well.

I also know that undbx is a free command line tool that will do it for you as well. http://thunderbirdtweaks.blogspot.com.au/2011/07/outlook-express.html

Hi, Matt;

Thanks for your reply.

First, re. the link to the dbx2mbx site: Try http://www.softspire.com/, then look under "Email Conversion" (on the left side of the page) -- "DBX to MBOX converter", which will take you to that page.

Thanks very much for the info and link to the free "undbx" app -- I will look into it!

However, as I read the comments at the undbx info site, I came across this line: "Thunderbird can only import mail from Outlook Express if the two programs are on the same computer.", and it reminded me (it's been a very hectic week!!) that I HAD imported my OE mail to TB on my old computer, AND that, within that version of TB, ALL my OE mail was there, and displaying properly. One would think that my problem had been solved, back then, but:

1) when I look at my old computer's C drive TB profile file, I see that only some of the OE mail that shows in the TB app (on my old computer) is actually there;

2) I also remember that I had, of course, imported that TB profile folder into the TB on my new computer, and -- naturally -- only those email that had actually been stored in that profile folder (ie, only a portion of what was actually showing in the old computer's TB app) had been imported.

These were the steps that led me to, first, think about giving up on TB, and, then, when I found the DBX2MBOX app -- and saw that it actually worked properly -- consider buying it, and staying with TB.

Of course, the nagging question is: if ALL my OE email is showing up in the TB app (itself, not its profile file) on my old computer, *why isn't that email also showing up in TB's profile file?* (Just in case you'd like to know, I found TB's profile file at (in my XP machine): C:\Documents and Settings\[username]\Local Settings\Application Data\Thunderbird\Profiles\nywshctd.default .)

Along a slightly different tack: one of the comments in the page that gives info on "undbx" implies that there's no need for any dbx to eml conversion app, because, within OE, one can instantly convert OE's dbx files to eml by going to File - Save As - eml. I tried this, and it *seemed* to me that this works per individual email, only. I'm not sure about this, though. IF this method would work for complete folders, with all their email contents, then it would seem that no conversion app is needed; on the other hand, it seems more probable that undbx's sole (and important) feature is to convert all the emails within a folder (or directory?) all at once. If you have any experience with this issue, Matt, I'd welcome your feedback. (I'd try it myself, but I'm not sure where OE then stores these self-converted eml files, and I don't want to corrupt my OE 'profile' directory any more than it may already be.)

Thanks for your interest and help, Matt!

If you are still about, I have stumbled on information that may be relevant.

If you install windows live mail is installs the files necessary for Thunderbird to import DBX files. SO install it, and use Tools menu (ALt+T) > import to import your DBX files. Do not choose everything. Choose Import mail and you will be asked for a location.

Hi, Matt;

Thanks for your continued support -- I appreciate it!

Yesterday, I downloaded the free command line dbx-to-eml tool that you had so kindly recommended (at http://code.google.com/p/undbx/ ), and, as I'd surmised, its function is to do what OE itself can only do per email -- that is, convert a .dbx to .eml format -- but do it by folder, which saves an eternity, and is much more elegant.

The dbx-to-eml tool was very easy to download and use, and I was able to ask it to convert all my folders at once (which amounts to more than fifty folders, and hundreds of emails). It did a great job, and I was able to designate the location of the resulting output directory anywhere I wished.

Because the dbx-to-eml tool saves the converted folders to any specified location, one can then import them to Thunderbird regardless of whether Thunderbird is on the same or a different computer.

I wanted to move all my OE email to a new computer (which involves a move from XP to Windows 7), and, in my case, this was easily achieved because I have the two computers' data drives linked by a home network (intranet): after converting all the OE folders from dbx to eml, I went to my new computer's instance of Thunderbird, and, using the Import-ExportTools Thunderbird add-on (https://addons.mozilla.org/en-US/thunderbird/addon/importexporttools/), I simply imported the saved eml folders, one at a time. It worked without flaw.

In a situation in which the two computers were not linked by a home network, one could easily save the eml output directory to a USB key, and have the new computer's Thunderbird import the eml files from that location.

I should also add that that command line dbx-to-eml tool is purported to also work as an on-going back-up utility: one can ask it to find and convert any subsequent new files in OE, and it will not only do so, but will also find their corresponding folders, in the original output folder, if they exist there from a previous operation.

I have yet to import all my newly-created eml files to my Windows 7 Thunderbird, but - so far - it appears that this should work smoothly.

Based on the various methods I researched -- and the few that I actually tried -- my opinion, so far, is that using the free command line dbx-to-eml tool, at http://code.google.com/p/undbx/ , is the easiest and most reliable way to move Outlook Express email files -- within their corresponding email folders -- to Thunderbird, whether within the same or different computers.

It would be neat if Mozilla could try this method themselves, and - if they should find it as fool-proof as I have - promote this as one of the first methods to use for moving Outlook Express email to Thunderbird. It will save others a great deal of time and frustration.

Matt -- your kind and generous help made it happen: thank-you!