Problem logging into Gmail from Thunderbird My wife has a problem with her gmail account, and as a security measure changed her password.
She has successfully logged in from her iPad and iPhone but Thunderbird on her MacBook seems to be caught in an authentication loop - we have signed on to google a dozen times.

I managed to enter her gmail account in Mail, so I am assuming there is some problem with Thunderbird.

All devices are using IMAP.

Can anyone suggest how we could reset Thunderbird - preferably without losing email on other accounts?

I deleted the account and created a new Account - unfortunately this failed with error Username or password wrong.
To simply reset the account, go to Tools > Account Settings. Choose the account, go to the bottom left of the screen (Account Actions) and click "Remove Account."  

Then re-add the account from scratch.

If you are using the IMAP protocol, you will not have lost any emails.

Though to be safe, you can navigate to where the data is stored and back this up first (usually in /Users/[username]/Library/Thunderbird/Profiles/)

If pop3, do the same as above but you will have to put the backed up pop3 emails back when you are done.