How to completely remove Thunderbird?

This will completely remove thunderbird from your system.

sudo apt-get purge thunderbird*

Here is what went wrong in your case.

  • You will need to wait for the locate database to update, or force update by sudo updatedb before the system picks the changes. Or use locate -e to print only files existing at the time locate is run.
  • The files you see in /usr/share/app-install belong to Ubuntu Software Center.
  • The files in /usr/share/icons belong to the corresponding icon theme.