import the folders how? Natively, or using some sort of addon?

Imported from where? and in what format?

I imported using Thunderbird/Tools/Import/ Import from another Thunderbird installation/ Choose a profile folder. Under Help/About Thunderbird it stated: 102.6.1 (64-bit). It also stated update to, which I wasn’t sure if that meant it was updated to, or if I should click it to update to. While trying to copy that for here, it updated. I haven’t restarted.

The installation I used for importing is a Windows 10 Professional computer.

My original source data was from a dead XP computer. From there I copied, using ‘copy’ in Windows File Explorer, the entire Thunderbird folder on the SATA HD to a flash drive on the Windows 10 computer. This became my actual source data for choosing folders within the Thunderbird folder profiles.

Note that I have not restarted since doing the import. Yet I can read the emails in the folders that have copied over. . Note too, I find that my browser, Firefox, doesn't print these pages properly. It omits information.

After writing the above reply, it occurred to me there was a slight possibility that the copy by the Windows 10 computer from the XP computer, via a SATA to USB cable I had just bought especially for the copy, had not worked.

Surprise surprise, I have discovered there are lots of reasons why Windows File Explorer copy doesn't work. I've checked the Thunderbird folders, using Windows File Explorer and couldn't find any files in the folders showing no files in Thunderbird. But I couldn't find any files either, in the first folder under the mail messages folder, where Thunderbird is showing files. The second folder shows some files but many are missing. I have the View set to show hidden files.

I've now realised I can do the import directly from the XP machine, via the SATA to USB cable, avoiding using copy, so I could try that.

But, the only reason I am trying to recover the files from the dead XP computer, was because I thought I had made the wrong backups, by only backing up the messages folder. On previous upgrades, for some reason I didn’t use the Thunderbird import facility, but just pasted the data into the new Thunderbird manually. But when I tried to do that this time it didn’t work. I posted this problem onto this support group but it was ignored.

I had read somewhere that you had to import a profile, hence my going back to the dead XP machine to recover the data higher up in the folder hierarchy, the Profile. But having now read the actual instructions, and you can import a folder, I have now realised, I have that folder from my backup of the XP machine. That copy is using the Windows File Explorer copy in XP and not Windows 10, nor via the SATA to USB cable.

So I am inclined now to delete the previous imports, restart and try importing the messages file directly into Thunderbird from my XP flash drive backup, thus avoiding the Windows 10 copy.

I should say that my Window 10 is crippled because of electricians causing an unplanned power cut when installing a new kitchen. Although Windows File Explorer appears to be working OK otherwise. I don’t want to sort out Windows 10 until I get another computer as a backup, in case that goes wrong and I don’t have access to a computer. If I can’t get the emails using my current Windows 10 computer set up, then I will wait until I get another computer and test with that. I plan to get other Windows XP computer or get the current one repaired, as a hedge against future problems with Windows 10 and 11. And get a new windows 11 computer. The Windows 10 computer is only a second-hand one to tied me over before I get a new Windows 11 computer.