It is possible to move the entire Thunderbird folder from one computer to another, both with TB 68, but the process doesn't always work without glitches. To manually move Personal Address Book and Collected Addresses, copy abook.mab and history.mab from the old profile to the new one, overwriting the existing mab files. The default location of the profile is:

C:\Users\username\AppData\Roaming\Thunderbird\Profiles\8characters.default

AppData is hidden by default. Help/Troubleshooting, Open Folder, will also open the profile folder.

Other address books can be transferred by exporting on the old (LDIF format) and importing on the new.

To copy mail, open Mail (for POP accounts), Mail/Local Folders (for local mail) or ImapMail (IMAP accounts) in the profile folder, then the subfolder named after the account, e.g. pop.gmail.com, and copy the mbox files - files with no extension, named after the folder, e.g. Inbox - to the Mail/Local Folders location on the new computer, while TB is closed. Folders will appear under Local Folders in the Folder Pane when TB restarts.

I did copy the local folders and IMAP file to a drive, and moved that to the new computer. I can see the files on the C drive. However, I'm still missing (aka doing something wrong) as they are not coming up when I open TB.

I think I need even simpler instructions. Thanks, sfhowes, for your help so far!

Did you copy the mbox files only (not the .msf files) into Mail/Local Folders of the active profile? Are any of the mbox files larger than 4GB? If there are, and you copied them to a FAT32-format flash drive, they would be empty on the C drive and the flash drive.

Just copied mbox files onto 2TB drive. Now move/drop them where?

I feel ridiculous at how much trouble I'm having! I guess this has to be treated as TB 101!

Are any of the mbox files larger than 4GB, and if so, is the external drive FAT32 or NTFS format?

My first reply explains where to copy the mbox files. Open the profile folder on the target computer, close TB, and open the Mail/Local Folders subfolder of the profile.

The mbox files are small. Still getting no where with the move. I (thought) I added to profiles

I can always resort to totally inelegant and move things as I need them. In a non-pandemic era I would drag to the box to a professional! Apparently I have become a technical dinosaur! Thanks for all the help, despite my lack of success.

How to put mbox (no extension) files that contain emails into the 'Local Folders' mail account.

In Thunderbird

• Help > Troubleshooting Information
• click on 'Open Folder'

a new window opens showing you the contents of your 'profile name' folder.

• Exit Thunderbird now - this is important.

• Click on 'Mail' folder to open and see contents.
• Click on 'Local Folders' folder to open.

You said you had "copied mbox files onto 2TB drive."

• Copy those mbox files on 2TB drive (right click on mbox file and select 'Copy')
• paste them into the 'Local Folders' folder. (right click in the blank area in 'Local Folders' folder and select 'Paste')
• 'Repeat until all the mbox files you have on 2TB drive are showing in the 'Local Folders' folder.

Start Thunderbird.