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not working on second start on new computer

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I migrated from a Win7 computer to a Win10 computer following this guide: https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer

The first time starting on the new computer works without problems, I can send and recieve mails as well as see my old mails. After closing Thunderbird the next start is not working right. I don't get asked for my Password, and all Windows are empty (see attached images).

Seems to be more than just a visual bug, because when Thunderbird recieves new mails, they are supposed to be deleted on the server, which they are not.


After the first run of Thunderbird on my new computer was succesful I deleted the profile on my old computer, using the copy of my profile, I was able to succesfully restore it there, without any problems starting it multiple times.

Have tried importing the profile multiple times, even tried to generate a new backup from my old computer and importing it again. The first start after overwriting the Thunderbird folder works without a flaw I noticed, then I close Thunderbird, and the second start is failing.

Does anyone have ideas, how to track down my problem?

I migrated from a Win7 computer to a Win10 computer following this guide: https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer The first time starting on the new computer works without problems, I can send and recieve mails as well as see my old mails. After closing Thunderbird the next start is not working right. I don't get asked for my Password, and all Windows are empty (see attached images). Seems to be more than just a visual bug, because when Thunderbird recieves new mails, they are supposed to be deleted on the server, which they are not. After the first run of Thunderbird on my new computer was succesful I deleted the profile on my old computer, using the copy of my profile, I was able to succesfully restore it there, without any problems starting it multiple times. Have tried importing the profile multiple times, even tried to generate a new backup from my old computer and importing it again. The first start after overwriting the Thunderbird folder works without a flaw I noticed, then I close Thunderbird, and the second start is failing. Does anyone have ideas, how to track down my problem?
Attached screenshots

Chosen solution

The problem where installed language packs on my old computer.

I could start Thunderbird on my new computer without problems, when replacing: - Thunderbird/Profiles/xxx.default/addonStartup.json.lz4 - Thunderbird/Profiles/xx.default/extensions.json in my active Profile before every start from my backup.

So the final solution was: - deleting language packs on old computer - doing another transfer as explained in the link from the original question - completly deleting the Thunderbird folder in Roaming - copying my latest backup there - since then it is running without problems

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Found this solution:

https://support.mozilla.org/de/questions/1320355

Both computers run on Thunderbird 78.6.0 in 32bit

The other solution, depending on Profiles, does not help me, because Thunderbird only knows 1 profile in my case, even if there are 3 subfolders in the Roaming/Thunderbird/Profiles folder. The selected profile is the one I got from my old computer.


Just to prevent an Thunderbird Add-On causing the trouble, I told Thunderbird to do the second start without addons, then I will get asked for my password, then i got a window where I could choose to start without Add-Ons and then i get this message (see attached iamge)

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Chosen Solution

The problem where installed language packs on my old computer.

I could start Thunderbird on my new computer without problems, when replacing: - Thunderbird/Profiles/xxx.default/addonStartup.json.lz4 - Thunderbird/Profiles/xx.default/extensions.json in my active Profile before every start from my backup.

So the final solution was: - deleting language packs on old computer - doing another transfer as explained in the link from the original question - completly deleting the Thunderbird folder in Roaming - copying my latest backup there - since then it is running without problems