''<p>Waybillrol [[#question-1570747|said]]</p>'' <blockquote>As soon as I click on the Thunderbird Icon to start Thunderbird I get a Yahoo Page covering over my Thunderbird page with no practical way to remove the Yahoo page permanently? This is like a scam page or something from a devious hacker? </blockquote> More likely it is yahoo asking you to allow Thunderbird access to your account for mail or contacts or calendar. I have not idea which of those it would be. It depends entirely on your choices when you set up the account. My guess something is not working because yahoo is not allowing access to the resource because you have not authorized it.