Noté 2 sur 5 étoiles

there was nothing in the trash nor on the serveur, and i didn't changed any settings
i used a backup (2 days old) to restore the mails.
my advice: before using this addon , check if the emails are in double in unified view AND in each folders. Do not use it if it's in double ONLY in unified

Noté 1 sur 5 étoiles

i lost all and every mail with this addon!!! not only the one in double!!!!!!

You likely did not lose anything, because, by default - the extension doesn't actually delete any messages: It only moves them to the trash. Please look in your trash folder, and you'll likely find all those messages.

To actually delete anything, you have to explicitly change a setting on the review dialog to perform a permanent deletion, then provide a second authorization when I warn you about deletion being permanent.