I recently tried to send a large MP4 file using the default file link add on. After repeated tries of crashing the system and failing to upload, I decided to try and use drop box. I imported it and tried to run it. It gave me a long code and told me I needed to paste this code: zv7hDbnKgtAAAAAAAAAAkoX0WDwH2fvOV5HHnvlYHos into my "Thunderbird Cloudfile or Cloudlink" or or something with "thunderbird" and "cloud" I'll be damned if I can find any such place in the T-Bird app to paste this code. I searched and found no reference to any "cloud" at all.