Rated 2 out of 5 stars

Yet Another Buggy Release!
Lightning is okay when it works but it's always been very buggy. The main problem is the most basic one - connecting and syncing with Google calender? Another major problem is that it doesn't notify you when it can't connect and sync, which can result in you missing appointments, arrgh! Never, ever, rely on Lightning as your main calendar; always check your phone or log-on to Google, which kind of negates this app really. I have just installed version 17 of Thunderbird and of course, true to form, Lightning has stopped working (again). Thunderbird is having problems connecting as well? I only got Lightning working by installing the 'Provider for Google Calendar' add-on which someone mentioned. I don't know why Lightning needs this add-on to work but for some reason it fixed the problem this time around; I've never had to use that add-on before, I just waited until Mozilla eventually fixed it. Does anyone at Mozilla actually use their own apps? I can't believe they release buggy applications like these, its getting really annoying. I'm thinking of looking elsewhere for a calendar and email client because of the constant bugs which should be removed before any release.

REPLY TO: Philipp Kewisch (Developer)
So, judging from your reply it's Mozilla that's at fault. If there's an upgrade, Mozilla don't inform the developers and the add-ons don't get updated in time - what a system! And as long as that system is in place it will continue to happen, resulting in more frustration for the end user. Users aren't interested in the politics of it all they just want software that works and Thunderbird - and consequently Lightning - is simple not reliable enough for everyday use. Years ago I used Outlook and had no problems, it just worked, but the cost was prohibitive. So being a long time Firefox user I thought I would change to Thunderbird and at first I was very pleased but then I came across bugs which never get fixed and are ignored. For instance, highlight your Inbox and your faced with a blank message pane, it doesn't show your first email which I thought would be logical. You have to click on an email for it to show up in the message pane so you can read it. Is that supposed to happen? It's been like that for years! The new Menu Button which is now shown by default, has disappeared? I've installed Windows Live Mail and have been using it for the last couple of days. The mail client is slick, it works perfectly and looks like just like Outlook. Also, if there are any connection problems with mail or calendar you can click on the status bar and an info box pops up with the all the details. You're not left looking at an very small triangle which can be easily missed and gives you next to no information. It's not perfect, because although you can connect to your Google calendar it's read only. Hopefully this will change in the future but for now I'll just login if I need to change anything, I'll also look around for any another options because I've had it with Thunderbird.

This review is for a previous version of the add-on (1.9).  This user has a previous review of this add-on.

I use Thunderbird with Lightning. I even use the beta versions for my main Email and Calendaring needs. I have subscribed to Google Calendars both via the Provider and via CalDAV. When it doesn't synchronize, a yellow exclamation mark appears next to the calendar.

Most of the issues users have with Lightning are the constant upgrade issues. This is not something we can easily fix, if you want to know why read about binary components. I am already working overtime during releases to get things in place, but if either addons.mozilla.org or the Mozilla Addons Manager itself doesn't tell you about the update for the Provider for Google Calendar (which was public even before Lightning), then that is not something that Lightning should be paying for (in negative reviews).

I have had the old version blocklisted for Thunderbird 17 to avoid more such issues in the future, but this is not something I can do every release.