Set the Default Browser in Thunderbird
Thunderbird usually passes the event off to your default web browser. Under normal circumstances, this all goes off without a hitch. However, if things go wrong, you need to know how to tell Thunderbird precisely which web browser you want it to use.
Pro Tip
By following the steps above, you can set Thunderbird to use a web browser other than the default one the rest of your computer’s applications use. It could be handy if you’re concerned about viruses coming in through emails and only want to view these web pages in a high-security web browser. Then, double-click network.protocol-handler.warn-external.http and network.protocol-handler.warn-external.https to set their values to True. And, you can handle HTTP-based URLs with one browser and HTTPS-based ones with another. Again, this could be something to consider for security and privacy issues. While you may trust your HTTPS (encrypted) requests to any of your installed web browsers, you may want your HTTP (non-encrypted) requests handled by a different browser. To change which web browser to use in the future, go to Thunderbird Preferences and scroll down to the Files & Attachments section. Next to http and https, select the dropdown under Action to pick a new browser.
