I am unclear on what you are asking. Here are the steps I always suggest, and most users report success, although it's easy to overlook details, which are important.

https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer

here is the info in brief steps:

1. ensure thunderbird is NOT running on old machine
2. enter %appdata% in search window on task bar and press Enter key
3. this should open windows file explorer in Appdata\roaming folder
4. highlight the Thunderbird folder and copy to external media
5. ensure thunderbird is installed on second computer, started once and NOT running
6. enter %appdata% in search window on task bar and press Enter key
7. you should be in Appdata\roaming folder , copy&paste the exported Thunderbird folder there. This may prompt to overwrite an existing folder of same name. allow it

#   start thunderbird and all should be there

Oh, a few things that need to be credited: The author reads,

1. Locate the master profile folder on the source computer as above. (Master profile? WHAT kind of profile, as is WHERE IS IT?)

5. On the source computer, copy the Thunderbird folders... (Should he just say THUNDERBIRD FOLDERS WHERE?)

6. The big one: On the destination computer, remove (or rename if you need a data backup or to preserve an old profile) any Thunderbird folders in the destination folders Windows(C:)/Users/~/AppData/Roaming and Windows(C:)/Users/~/AppData/Local directories.

Huh? It makes sense when he writes (kind of),

"On the destination computer, remove any Thunderbird folders in the destination folders Windows(C:)/Users/~/AppData/Roaming and Windows(C:)/Users/~/AppData/Local directories."

It seems as though you're DELETING Thunderbird folders, and planning to dub in YOUR OWN Thunderbird folders that you copied in the same place on the SOURCE computer

That's what I thought, but it DOESN'T WORK.

Was it because I used Thunderbird 145? Will it work if and ever I find version 144?

Thanks guy, if I know anyone will respond to this.

Hi there,

I should have put in it I had a stroke a couple of years ago. Frustrating!

Three points:

1) You're talking about " Appdata\roaming folder" but what about Appdata\LOCAL folder? Do we need to dub Thunderbird to the LOCAL folder as well as ROAMING?

2) Also, I get no answer dubbing it. No overwrite message.

3) And IF the original Profile on the DESTINATION computer is wrong, I get a message that Thunderbird WILL NOT WATCH. I get "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible."

4) On installation, 145 continue to WATCH us work. I couldn't just not start it.

One thing that will help is be able to find HOW MANY PROFILES DOES THUNDERBIRD recognize? The date of the profile that makes sense?

Thanks. Your helping is helpful. (It's also using SOURCE destination (Windows 11) and DESTINATION computer (Windows 10). More clear.

The LOCAL is not necessary. Thunderbird can work with only one profile. It sometimes accumulates many, but they're just baggage. The inaccessible message happens if the desired profile and associated profiles.ini are not loaded together. The purpose of using the thunderbird folder and not the profile folder is that the thunderbird folder includes both. Here is what happens: thunderbird opens the profiles.ini but the profile it is identifying isn't there. That can be an easy fix, often by overtying in the profiles.ini the actual location. this is avoided when the thunderbird folder overwrites the default thunderbird folder. what often happens is the user pastes the transferred thunderbird folder to the appdata\roaming]\thunderbird folder which creates appdata\roaming\thunderbird\thunderbird - and that is why I state that a prompt to overwrite should happen.

Hi there,

So given in that article, LOCAL wasn't needed as much as the Roaming. Until your advice though, I'll leave out LOCAL Thunderbird. I assume it will create the Thunderbird make it.

It has me confused that you are referring to profiles.ini, but I checked and now I see it under Thunderbird. It seems I could not make the transfer of Thunderbird, because I don't have ANY of those profiles.ini. I'd have to add them in at the end.

QUESTIONS:

1. Is it OK for me to allow Thunderbird opening after installing? (I'd shut it done afterward.) 2. WHY does the Thunderbird which profile it chooses? The newest one? 3. Are older Thunderbirds of versions lower than 145 any where?

I really appreciate your input. Thanks.

(I'm trying to put the ORIGINAL directions. I hope it won't cut off. Thanks.) https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer

An alternative method for manual transfer between Windows 10 and Windows 11 computers

This section assumes you have a default Windows installation and will work on computers upgraded to Windows 10 from previous Windows versions.

Locate the master profile folder on the source computer as above. Locate the master profile folder on the destination computer as above.

Note out of interest that your username (indicated by ~ below) on the two computers might be different due to legacy issues, but it will make no difference with a manual transfer as below

Close Thunderbird in both computers.

On the source computer, copy the Thunderbird folders in both Windows(C:)/Users/~/AppData/Roaming and Windows(C:)/Users/~/AppData/Local to your transfer media, in separate folders so you do not overwrite them.

On the destination computer, remove (or rename if you need a data backup or to preserve an old profile) any Thunderbird folders in the destination folders Windows(C:)/Users/~/AppData/Roaming and Windows(C:)/Users/~/AppData/Local directories.

Copy from your transfer media the correct Thunderbird folders into the two folders above to replace the ones you have removed or renamed.

Restart Thunderbird on the destination computer and test it, noting that your inbox tab should be identical to source, but that other tabs may have opened with Thunderbird messages.

(I'm trying to put the ORIGINAL directions. I hope it won't cut off. Thanks.) https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer

A reliable alternative method for manually transferring files between Windows 10 and Windows 11 computers is to use a direct external drive transfer. Simply copy your files onto a USB drive, SSD, or external hard disk from the Windows 10 PC, then connect the same drive to the Windows 11 system and move everything over. This method is fast, secure, doesn’t rely on internet speed, and works even if the computers aren’t on the same network.

You can also use handy tools like shared folders or LAN transfer if both PCs are connected to the same router. And for people who prefer app-based solutions, pairing this method with a helpful utility like the magis makes organizing and managing your files even easier.