Open the profile folder, with TB closed, delete logins.json, cert9.db, key4.db and pkcs11.txt. This will remove all account and master passwords, and the files will be automatically recreated when TB restarts.

http://kb.mozillazine.org/Master_password

What profile folder ? Where do I find it ? Thanx

What profile folder ? Where do I find it ? Thanx

http://kb.mozillazine.org/Profile_folder_-_Thunderbird

W10: C:\Users\username\AppData\Roaming\Thunderbird\Profiles\zzzzzzzz.default AppData hidden by default.

No sfhowes, this does not solve the problem, probably because there was no such file as logins.json in any directory and the other named files are found in the Firefox directory, not Thunderbird!

However, the proper way to achieve this, I found is to start Thunderbird: Choose Tools -> Error Console Next paste the expression:

openDialog("chrome://pippki/content/resetpassword.xul")

Then press the Evaluate button. You'll have to go through some additional safety steps, and ALL passwords are erased!

For others reading this topic, logins.json, cert9.db and key4.db are found in the profile folder for current versions of TB. The question owner must be using an older version, which had different files, since they reset the master password with an obsolete command.

https://support.mozilla.org/en-US/kb/protect-your-thunderbird-passwords-master-password#w_removing-your-master-password-if-the-master-password-has-been-forgotten

Thank you for your help. I used the file explorer but could not get it to work with the link. I see where I put my username - what are all the z's ? I am guessing the link ends after the word default ? "AppData hidden by default" is not part of the link ? Tom

Inn TB, Help/Troubleshooting, Profile Folder, Open Folder to open the profile folder in File Explorer. Close TB before changing any files. The zzz... indicates the string of 8 characters that is different for every profile.

sfhowes, I appreciate your help, The problem I am having is that I can not open Thunderbird - it first asks me for the Master Password - which I do not have. I did not save it properly or ? Your information is very informative - getting closer all the time. Once I get into T-bird I can use it to correct many things. Thank you, Tom

You can open the profile folder without opening TB, and after you delete the 4 files TB will open without asking for a master password.

I deleted the four files, then tried to install Thunderbird again, it tells me that my Thunderbird profile can not be loaded. It may be missing or corrupted.

I deleted the four files, then tried to install Thunderbird again, it tells me that my Thunderbird profile can not be loaded. It may be missing or corrupted.

I do not intend to be a nuisance, but I appreciate your help.

I deleted the 4 files. I reset all passwords. I am still asked for the lost Master Password - which I do not have - and refused entry to one of my accounts.

logins.json cert9.db key4.db pkcs11.txt

Make sure you deleted the 4 files, while TB was closed, from the correct profile folder, as many users have multiple profiles apart from the (Default) one that launches at startup. Help/Troubleshooting, about:profiles, to see the status of all the profiles, and buttons to open the folders.