I am only a casual user of Linux, but did upgrade my Linux Mint Mate recently with no changes. I don't know Ubuntu, but - worst case - you can let Thunderbird finish basic profile setup, exit TB, and the copy the contents of the .thunderbird's embedded profile to the new profile, and then restart TB.

Hm, no joy on that. I tried to use the import profile tool, but that didn't work, got an error message, nor did copying the old .thunderbird folder over the new one at usr/run/1000/location.

No biggie. Thanks for your help; what I was trying to avoid was setting up new accounts for all my old ones, then figuring out where exactly the old mail file location was, which is a bit of work, but likely less than reinventing the wheel on this one.

Just to clarify, I didn't mean to imply copying the .thunderbird folder - just the profile folder contents.

OK, what I finally figured out is that the profiles migrated to the /snap directory, which is where both the .mozilla (firefox) and .thunderbird folders live. When I dumped the contents of my old folder into those locations, it worked. What had me bolloxed was the location of those folders in my old home folder, and not buried in the /snap subfolder.

Thanks!!!

You're welcome.I was glad to assist.

I just want to confirm the same experience.

Thunderbird 115 included in 24.04 LTS installation.

My profiles are located on the SD card working well on other two laptops running ubuntu 22.04. Swap SD cards with profiles between two laptops is my way of working with Thunderbird since 13.04.

After installation 24.04 (and Thunderbird 115.10.1 included). Following the instruction for adding old profile to the new Thunderbird. Help->Thunderbird information->about:profiles. Creating new profile.

Using the function CHOOSE FOLDER indicated the path to the profile /media/VB/AB49-E208/Thunderbird profile The path to the folder shown by Thunderbird is different (and strange): /run/user/1000/doc/58235/Thunderbird

When looking into the directory tree the folder is empty (obviously).

Thunderbird therefore cannot reach the profile located on SD card and doesn't work. How could I overwrite the strange path by the right one ?

This kind of "portability" was the very attractive feature since several years. Should snap version break it I'll have to look elsewhere.

Thanks all for the help. The first migration I did worked well by dumping the old ./thunderbird into snap/thunderbird/common.

But it didn't work the second time around, in which case I had to set up each new email address as a new account, then figure out which subfolder to point them to in the server settings for the account.

Tedious, but, no other choice.

Used to be so much easier to do this, before snap . . .