Hi

You should not need to install Lightening with Thunderbird as it should have it installed already.

If you look to the top right of the Thunderbird screen, you should see a little notepad type icon with a number 7 in it. Click on this and the calender should open.

I hope this helps, but if not, please come back here and we can look into a different solution for you.

Before the update of Thunderbird this morning, Lighting work great. After the update, it would not install Lighting. An error message showed up that it was not verified.

I've heard of reports like this. Please post a screen shot. See https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem