Migrate from Outlook to Mozilla Thunderbird

1. Download app to c:/apps/thunderbird or wherever you usually download application installation files. [can be anything]
2. Create the folder where you want your mail to be stored, like c:/mail [The directory can be anything, but my directions assume this value.] Yes, you can just use the default values of Thunderbird, but that buries all your data in c:/documents and settings/administrator/application data/thunderbird or some such, and that makes it easy to overlook and forget to back up.
3. Install Thunderbird, choosing "custom" and then "local support"
4. When asked whether you want to "run Thunderbird now", choose NO. (This is important.)
5. Click the Start button, choose Run.
6. Enter "C:\Program Files\Mozilla Thunderbird\thunderbird.exe" -p [WITH THE QUOTES and the -p flag. This will launch Thunderbird in "profile editing" mode.]
7. Create a profile. Give it a name, like your initials. When asked to choose a directory to store settings and mail, choose c:/mail or whatever it was you created in step2 above.
8. Choose to Start Thunderbird. When asked if you want it to be your default mail client, say no. (More important than it seems.)
9. Thunderbird will start up.
10. Set up your primary email account right now, entering in your POP/IMAP server info, etc.
11. When that's done, go to tools:account settings:server settings. Make sure the path for local directory is c:/mail/something/something.
12. Go to tools:account settings:local folders. Make sure local directory says c:\Mail\Mail\Local Folders

Time to import your Outlook messages! These steps will result in a folder within your Thunderbird profile called "Outlook Mail."

1. Leaving Thunderbird open, open Microsoft Outlook. Outlook is supposed to be your default mail program during importation, though I am not sure how critical this is. To make sure that it is:
1. On the Tools menu, click Options, and then click Other.
2. Under General, select the Make Outlook the default program for E-mail, Contacts, and Calendar check box.
2. Now go back to Thunderbird (leaving Outlook open), and choose Tools:Import.
3. Choose "Mail" and click Next.
4. Choose Outlook and click Next. The importation will begin. It can take a long time.
5. It may get hung up on oddly named messages and draft messages, and your virus software may kick in. You may get an error message ("Can't create draft message %PO%...Check your Temp Directory setting" [screenshot]) and have to click "OK" literally hundreds of times. (This happened to me.) Eventually, though, the errors should clear. The fastest way to get through them is to just hold your Enter key down. I have no idea what Temp Directory setting Thunderbird is referring to.
6. When the process completes, all your old mail will be in the folder called "Outlook Mail" under "Local Folders." You can optionally move it around to other folders, but be careful: there may be some irregularities that may result in your messages disappearing. When I tried moving whole folders up into a folder I created under my profile, I got very erratic results, and whole messages disappeared. Folders acted oddly, and then were empty when I restarted the app.
7. My advice for right now is to be satisfied you got your Outlook messages into Thunderbird. Re-arrange them later, perhaps when Thunderbird is more fully developed.
8. You can, however, repeat the importation process for your Address Book. Note that there also seem to be some irregularities, here, too. For instance, if an Outlook contact has multiple home phone numbers, I think only one gets carried over to Thunderbird. This may be true of email addresses, also.