Due to issues with Windows10, I decided to change the last of my computers to Linux Mint 21.3.

The plan was to back up the Thunderbird profiles (as usual) on my main desktop to a flash drive, install Mint and then copy the profiles to the Thunderbird that is preloaded with Mint; I have moved Thunderbird numerous times on various computers to new computers and/or new installations. Example: from Win95 to Win98, Win98 to Win7, and Win7 to Win10 without incident. This is my first time performing a Thunderbird transfer to Mint although I have performed quite a few Mint installations.

Unfortunately, after backing up the Thunderbird profiles and other vitals, and successfully loading Mint, something went terribly wrong. After the final reboot required by Mint, files on an external portable ss drive starting being erased, and then the Mint OS on the C drive of the computer would not start.

The computer would not allow me to install Mint again so I loaded Windows7 (since the upgrade to Win10 was done as instructed on the M$ site so I did not have an installation disk or image), and released the secure boot. Then Mint was able to be installed but presented a new challenge.

The challenge is the Thunderbird structure in Mint is different than the Thunderbird structure in Mint. Although I created one of my email accounts in Thunderbird on Mint, there is not a profile I could locate. Therefore, the profiles from Windows cannot simply be copied and then the pkcs11.txt deleted. Therefore, although I have the data, I do not know how to use it or recreate the email accounts. I dread the thought of purchasing a small computer with Win10 just so I can access my email accounts and numerous folders of email. However, at this time I may not have any choice. Not sure if there are any repair shops that could "fix" the problem.

In the past I would simple copy one email account at a time, msf files and .sbd sub-folders, but again, I cannot locate a profile or even an email account in Mint for Thunderbird.

Can this issue I be resolved, or am I trying to go up the creek without a paddle? This is the first time that I can recall not being able a solve a software problem. I have also never had a problem with any Ubuntu or Mint installation although there are always issues with Windows.

Mint is derived from Ubuntu. Ubuntu changed all applications to SNAP installers. These are sandboxed and have caused innumerable issues since the release of 24.

The simple solution is uninstall Thunderbird from mint, download the flatpak from thunderbird.net and reinstall it. OR get a distribution where there are thinking people in the decision making process other than the security mafioso concerned with locking everything down regardless of the inconvenience.

Thanks Matt and I sincerely appreciate you responding. I am going to try your suggestion later today.

BTW, totally agree with you about "the security mafioso concerned with locking everything down regardless of the inconvenience.", and I'm pretty sure security expert Mikko Hyppönen would too.

Uninstalling the pre-installed Thunderbird and installing the flatpack version, which appears to be the same version and size, but may not be, did not resolve the issue. There is still no "profile", as in Windows, to copy my old files into even if I create a new profile using one of my email accounts after installation of the new Thunderbird flatpack, which is necessary just to access it. A profile under Thunderbird in Mint either simply does not exist, is hidden and/or protected, or can be found. Do you know the path and if so can you provide it?

From my research, Thunderbird profiles and its code are suppose to be the same whether Windows or Linux. However, that does not appear to be the case unless I am looking in the wrong place, or a special app and/or program is needed to view the profile in the Mint structure.

FYI, the Thunderbird that was in Windows10 was downloaded from the Mozilla web site and updated and upgraded upon receiving notifications. It worked well with three email accounts from gmx, one from gmail, and one from Spectrum. Even made a small contribution at one time since I have been using it for years, starting with Netscape.

Unfortunately, looking more like I am going to need to purchase a small computer with Windows10, install Thunderbird on it, and then copy the Thunderbird profiles into it so I can access all my old mail.

Never would have imagined transferring Thunderbird profiles from Windows 10 to Linux Mint would be so difficult. However, not giving up. Just have not learned a method how to do it..... yet. Also refuse to believe I am the only person that has experienced this issue unless everyone else just gave up.

FINALLY, figured it out and it was actually incredibly easy. Slapped myself. Operator stupidity. Was expecting process to be difficult.

Gave up looking for the path to the profiles in the Linux Mint structure and focused on Thunderbird itself.

Put on strongest pair of reading glasses, then tested each TB profile on two different machines before installing on main desktop since was not certain which profile was most recent.

Installation was simple and easy.

1) By default, Thunderbird opens by default to "Set Up Your Existing Email Address".

2) Need to click on the three horizontal lines in the upper right.

3) Select Tools, then Import.

4) Select Import from another Thunderbird Installation.

5) Chose a profile folder.

6 Although progress was not displayed on the bar, process was completed in about five minutes after which FINISH was displayed. Not concerned about the progress meter not moving as the process worked.

Thunderbird opened with all content; accounts, messages, Local Folders (Where old messages are categorized and stored) and address book.

Each email account took a bit to load as the summary file for each inbox had to be built.

Appearance and format for Linux Mint is different than in Windows 10 but it is easier to read and is cleaner. Like it. Why I use Thunderbird.

Will be making a donation next month.