Tick the box to remember under the text box you type the password into when asked.

I don't have that option, I read about there being a tick box but I haven't seen one when asked for a password.

When asked for password you should see this window. select the checkbox to 'Use Password Manager to remember this password' see image.

If the 'Use Password Manager to remember this password'checkbox is missing:

In Thunderbird 'Menu icon' > 'Options' > 'Options' > 'Advanced' > 'General' tab click on 'Config Editor' button it will say to be careful :)

Intop search type: signons Make sure following lines are set to True. Note: double click on line will toggle from 'False' to 'True'

• signon.rememberSignons
• signon.rememberSignons.visibilityToggle

close window - top right X click on OK

Restart Thunderbird Enter password at prompt and select the checkbox. click on OK

Otherwise are you using anything like a password manager called Sticky Passwords. Remove Thunderbird from it.

Also if you are using a product like CCleaner or similar which can clean up files then do not allow it access to any thunderbird file or folder. It has a habit of deleting various files such as passwords, session data etc.

Thank you very much for your help, removing the sticky password extension gave me back the password manager prompt. I checked the signons and they were both true. I thought I would post my actions to resolve this issue for future reference.

I had this problem too. I did this check and mine were set to true. I toggled from true to false then back to true. Restarted Thunderbird. Works now.