Today when I logged onto my MacBook I found that my Thunderbird desktop application is corrupt. When I attempt to open it states "You can’t open the application “Thunderbird” because it may be damaged or incomplete." Screen shots included. I last used TB with no issues on Oct 27th. I have over 20 years of TB emails that I do not want to loose. I have backed up my profiles folders (there are 3) from >Go>Library>Thunderbird>Profiles My first question is that I thought there were multiple locations of profiles. One for local. But I can only find the above profile. My second question is how to I go about re-installing? Should I remove the corrupt application first and and then reinstall? What steps should I take? Thank you!