What Operating System are you using Windows , Mac, Linux ? What version of Thunderbird are you currently using? What was the previous version? What do you mean by 'Thunderbird Quit' ? Do you mean you click on the shortcut and it does not start up ? Do you mean it starts up but asks you to create a mail account? Do you mean it starts up and seems to be downloading mail but the folder pane is empty ? Please explain the problem and upload images to help explain the problem. If you get any error messages then what is the error - word for wordor better still upload an image which shows the error message. What type of mail account are you using Pop or Imap or both ?