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Problems for Thunderbird installation with Win11 for 2 Pc's (LenovoT14 + HP15")

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  • Last reply by david

multiservices
multiservices

We tried installing Thunderbird on two PCs, both running Windows 11, but with unsatisfactory results. In July 2025, we bought a 15-inch HP PC running Windows 11. Thunderbird was installed, and the sending and receiving functions worked correctly with one domain name and three email addresses linked to that domain name. In January 2026, we bought a Lenovo T14 PC running Windows 11. We tried installing Thunderbird with the same domain name and three different email addresses linked to that domain name. Result: On the T14, it was impossible to install the third email address; only two addresses could receive and send messages correctly. Furthermore, the 15-inch HP PC now receives messages but can no longer send them; the connection is rejected by the server. Analysis: Apparently, there is an inability to coordinate the two PCs for Thunderbird. Question: Windows 11 had numerous updates between July 2025 and January 2026. Do both PCs need to have Thunderbird installed the same version of Windows 11 ?

We tried installing Thunderbird on two PCs, both running Windows 11, but with unsatisfactory results. In July 2025, we bought a 15-inch HP PC running Windows 11. Thunderbird was installed, and the sending and receiving functions worked correctly with one domain name and three email addresses linked to that domain name. In January 2026, we bought a Lenovo T14 PC running Windows 11. We tried installing Thunderbird with the same domain name and three different email addresses linked to that domain name. Result: On the T14, it was impossible to install the third email address; only two addresses could receive and send messages correctly. Furthermore, the 15-inch HP PC now receives messages but can no longer send them; the connection is rejected by the server. Analysis: Apparently, there is an inability to coordinate the two PCs for Thunderbird. Question: Windows 11 had numerous updates between July 2025 and January 2026. Do both PCs need to have Thunderbird installed the same version of Windows 11 ?

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david
david
  • Top 10 Contributor

I generally recommend that, when setting up a second PC, to just copy the working setup from the first PC.

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 WILL prompt to overwrite an existing folder of same name. allow it 
#   start thunderbird and all should be there

The second PC should be equal or NEWER than the first PC. That is, copying to a newer version is good, copying to an older version is not.

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