Hi, need to know where you used the envelope to configure your address please and if it was Thunderbird please see here : https://support.mozilla.org/en-US/products/thunderbird

Firefox not Thunderbird. The envelope symbol to initiate sending an email link is located in the menu feature (three horizontal lines in the upper right hand corner).

Hi, please see - Change the program used to open email links

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Here is an example: currently the default mail to is name@hotmail.com which was set up the first time I used "email a link to this page" . Now I need to change the default mail to newname@hotmail.com. I have not been successful with any suggestion so far. Thanks for any help you can give.

Hi, Options --> Preferences --> Applications that only selects the application to use for mail and has nothing to do with the email address it self. What application is it set to use ? What application do you want it to use ?

Ok, your version 52 https://support.mozilla.org/en-US/kb/change-program-used-open-email-links

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