I recall seeing the same issue a while ago. Back then, the reason it was RED is because the contact is not in any of your address books.

There was also a bug report which discussed red font when email address was in address book, but that was fixed some time back.

I've retested this even in Safe Mode and this is not occuring for me in the latest versions.

What Operating System are you using? What version of Thunderbird are you using?

What theme as you using?

Do you get the same problem if you restart Thunderbird in 'Safe Mode? https://support.mozilla.org/en-US/kb/safe-mode-thunderbird

I have the same issue. And, yes, it only happens to email addresses that are not in an Address Book already. Does anyone have a fix? I am using Thunderbird 71 on Windows 10.

David Berman

I presume you are using a beta version and have just updated. What version were you using prior to updating and did this red font colour suddenly occur when you updated to beta 71 ?

I did not get an email about responses. Hence the super late response. This problem is no more it seems. Thank you for responding. I wish I had known earlier, to have thanked you sooner!