I have noticed a few reports that Lightning 2.6.4 is not working with the Debian variant of Thunderbird, called Icedove. Together with one of our users (thanks Arie!) this was reported to the Debian package maintainers.
There are slight differences in how Icedove and Thunderbird are compiled, the result is that the Linux symbol versions required are different. The maintainers are working on fixing this, in the meanwhile all you need to do is make sure you are using only one source for the packages:
- If you are using Icedove, make sure you install and use iceowl-extension instead of Lightning.
- If you are using Thunderbird from mozilla.org, make sure you are using Lightning from addons.mozilla.org. You can install it into /opt if you don’t want to conflict with your Debian packaging system.
Unfortunately, this difference in compilation has cost us some negative reviews. If everything is working for you or this post has helped you to use the right versions, please show some love and write a review ♥.