You can tell Thunderbird to remember the password. Note the check box in the password prompt pop up.

Yes, thank you christ1. Now I find that I can launch Thunderbird and access all eight accounts without entering any password except the master password.

I would like to revert to the previous setting which required a separate password for each account, and then never again unless I closed Thunderbird completely. Is it possible to return to the previous arrangement?

Thanks

spruce18b

I would like to revert to the previous setting which required a separate password for each account ...

This has always been the case, and hasn't changed in ages.

... and then never again unless I closed Thunderbird completely.

It doesn't work that way. You can either enter your password manually whenever it is required, or you can tell Thunderbird to remember your password, so that you don't have to type it again and again. That doesn't change the fact that you do need a password in the first place. It cannot be disabled.

Now I find that I can launch Thunderbird and access all eight accounts without entering any password except the master password.

The master password protects your account passwords. It is a useful security measure. When you're being prompted for the master password (now called primary password) you did deliberately set the master password at some point. You can remove the master password if this is what you want, but it's not recommended.