I understand your frustration, sometimes I get the same issue and usually it's from people who sent email via a phone. This only occurs if you are viewing in html. Basically, a link is only a clickable link if the email contains the correct html code for http to make it a link and the code does not include that vital information - poor coding! However, if you change to viewing in Plain Text, it will force the text to become a link. This is because there is no formatting (html css code) in Plain Text emails, so Thunderbird will detect text and create the clickable link. 'Menu app icon >'View' > 'Message Body as' > select 'Plain Text' Or quick access via keyboard - press and hold 'Alt' key, then press 'V' then 'B' then 'P' to return to 'Original HTML' - press and hold 'Alt' key, then press 'V' then 'B' then 'H'