Hello there Thunderbird stopped working. With the message : message, "can't load xpcom" This message is there because files are corrupted, or missing or mismatched following after a mismatched or failed update. '''''Deleting all folder from thunderbird''''' Make an backup from the profile and be sure it s safe. Be sure that Thunderbird is deleted and all is deleted from the system if possible use a software cleaner. Use a new the latest thunderbird installer. https://www.thunderbird.net/en-US/thunderbird/all/ Be sure that you do not simply overwrite the old version on the desktop. '''''Disabling the antivirus''''' In the meanwhile disable the anti virus and firewalls and Vpn service for a good moment. To be sure that these services aren t blocking something. Also antivirus can block certain files after updates. '''''Renaming folders''''' If the reinstalled aren t working try to rename the existing Thunderbird map into oldThunderbird map and try to reinstall again. You cant reinstall the new version because all of the software has to be deleted from the desktop and system. Try to use the software cleaner like cc cleaner from google.