''<p>everratti [[#question-1403203|said]]</p>'' <blockquote> YOU NEED A REPAIR MODE THAT GOES INTO THE PROGRAM AND CHECKS THE FILE AND REPAIRS OR REPLACES MISSING OR BROKEN OR DAMAGED FILES </blockquote> There is one, it is called a reinstall. Thunderbird separates data and program, so reinstalling only changes things about the program install and system integration. I do not think your problems however will be related to Thunderbird being somehow corrupted. That is fairly rare. Perhaps take the time to describe what the issue is. From my 10 years or more supporting Thunderbird I consider the #1 cause of Thunderbird having issue post update to be third party anti virus products messing up. Resulting in no mail, odd connections error and password problems. But they are by no means the only cause of issues.