Some thoughts: - never assume that your software is moved somewhere without checking (ok, end of homily..) - if you want the profile elsewhere, i would - if profile already exists, copy to whichever drive you prefer using File Explorer -- click help>troubleshootinginformation -- scroll down to 'profiles' and click 'about:profiles' -- click 'create profile' in upper left -- click next -- enter a short name for the profile and THEN click the browse button to locate and select the profile you placed externally -- for periodic backups, exit TB and use File Explorer to copy the profile elsewhere

I defer to others about Firefox

Thank you, David for your homily and thoughtful response. The question I still need answered is, "Is it safe to download the latest version of Thunderbird and answer all the 'new User' questions." I am concerned that that might overwrite my profile file. I will appreciate your answer, and on behalf of ALL the users you have helped over the years, THANK YOU!

Difficult to give an easy answer. If you install and are prompted to enter email id, that indicates that Thunderbird did not recognize your profile and is creating a new one. If the addressbook is empty, that confirms it. To ensure you do not lose anything, I always suggest copying profile elsewhere 'just in case' of a loss. For Windows, profiles are stored at c:\users\<yourid>\appdata\roaming\thunderbird\profiles

For SAFETY, copy the thunderbird folder, not just the profiles folder.

Hi & thank you David. Your last two messages were very helpful. The Thunderbird download preserved all my data--glad I had followed your copy advice anyway! This was the most serious of all the issues I caused myself, but applying a little knowledge, common sense & a LOT of time, I am back in business.

Now to tackle the problem of Dell/Win11/OneDrive filling up my tiny C: with Data. Who thinks to organize a system to pour data onto a 200GB drive and leave a 900GB drive virtually empty?!

I can only hope to get help from people who are as knowledgeable, patient & kind as you have been!

Best wishes for health, happiness & prosperity for you and your family, Ken

A simple way to offload your accounts from c to d is to do this: - exit thunderbird if running - copy the profile from wherever it is on drive c to drive d. Name it something simple to remember - open the profiles.ini file at c:\users\<yourid>\appdata\roaming\thunderbird and change it to point to drive D. This needs to be the explicit location for Thunderbird to use to access the profile (DO an BACKUP of profiles.ini FIRST) - start thunderbird and make sure all is well. You can confirm all is well by clicking account settings and then server settings and note that the bottom line of pane is pointing to drive d. - you can now delete the profile folder itself on drive c. that leaves only the appdata\thunderbird folder You now have all thunderbird data on D. - for backups, just exit thunderbird and copy the D profile to external media. I also encourage copying the appdata\thunderbird folder to make it easier for any future reinstall.

And, thank you for your kind words.  :)