Sometimes there are interruptions to thunderbird from other sources, such as antivirus. Your profile may still be there with all content. You can see that by these steps: - click help>troubleshootinginformation - scroll down to 'profile folder' and click 'open folder' - you are now in profile, in windows file explorer, click back one folder so that you are in the 'profiles' folder Is there more than one profile showing? If so, browse the content of both. Yours will have account info in either the imapmail folder or the mail folder. If you confirm the right profile, your next steps are these: - in thunderbird, click help>troubleshootinginformation - scroll down to 'profiles' and click 'about:profiles' - click the 'create profile' button - click 'next' - enter a short nickname, such as LOSTPROFILE and then click the 'choose' button to locate and select the profile you discovered, then click finish and launch.