Check and Send

Rated 5 out of 5 stars

deur Zileph op Mei 22, 2026 · permalink

A very useful tool! The popup can check for many problems and shows all of them in a nice list.

The English in the configuration screen is a little confusing, until you understands that "Popup <something>" means "Check for <something> and if found then show a warning about that". For example "Popup all recipients" means "Show a warning for all recipients" (if you want to double-check the recipients before sending an email I suppose).

The only minor grief I have is that you can't configure the add-on to also check for an empty subject field and/or message. Thunderbird warns about an empty subject field by itself with it's own popup. But it would be nicer if everything was listed in the add-on's popup with everything else.