So unreliable ... Rated 2 out of 5 stars

I'm syncing my calendars via FTP with *.ics files on shared webhosting platform. When Syncing via bad WiFi connections has corrupted my calendar files so often that I started making backups on a weekly basis. Disappearing and locking calendars (or lightning itself) finally (after > 5 years) made me switch to big G. Works flawlessly but I'd have rather stayed with a more private solution ...

disappeared and wont reinstall!!! Rated 1 out of 5 stars

How can I review something that disappeared altogether? It was working fine then disappeared, and I have tried to uninstall and reinstall several times and it just won't. Useless.

SLOOOOOW lightning Rated 1 out of 5 stars

Thunderbird went from a 10 second startup to somewhere north of 150seconds. Not lightning speed.
Have disabled that and the Google calendar Sync now all good. Not sure if its one of both add-ons that cause the problem

What's this mess? Rated 3 out of 5 stars

Thunderbird major upgrade v38 killed my profile, no more calendar no tasks either...
Lightning is not showing in extensions...
Reinstallation... restart .... gone again...
It's a very long time to rebuild a complete profile! It's a major problem, please provide a fix ASAP or clearly advice users to start configuration from scratch!
... Strange but after disabling auto update for all extensions and restart TB with missing Lightning ... It's getting back ... syncing ...

This user has a previous review of this add-on.

Mac OS X - all 30 sec. beachball Rated 1 out of 5 stars

Sorry - awful version - lightning with caldav ... urgs. always beachball - when I disable Lightning Thunderbird works like a charm.

Sending invitation not working Rated 5 out of 5 stars

Everything is working very well (with several calendars)
But when creating a meeting and choosing attendees, the checkbox "inform attendees" is grayed and no mails are sent to the attendess

Good Features but too laggy Rated 3 out of 5 stars

I really enjoy using Thunderbird and Lightning is very useful, but it hangs for about 2 seconds whenever I check or uncheck tasks. I use only a personal calendar (home) and set some tasks to repeat forever.

El complemento ideal para Thunderbird Rated 5 out of 5 stars

Lo mejor que existe para administrar tu agenda.
En una actualización Thunderbird lo incorporó y en otra lo quitó, no entiendo el porque, realmente Thunderbird sin Lightning es un producto incompleto, con esta extensión supera a Outlook.

It's Not Gone Rated 4 out of 5 stars

It's not gone, it's just integrated. Go to "Events and Tasks" either on the menu or the menu bar and click on "Calendar." Works like always.

This review is for a previous version of the add-on ( 

Lightning is gone for several times! Rated 1 out of 5 stars

Warum um alles in der Welt verschwindet mein Lightning-Terminkalender jetzt schon zum zweiten oder dritten Mal nach einem Update von Thunderbird? Auch Termine in Mails (via Outlook) werden nicht mehr angezeigt. Ich will zwar nicht, aber ich werde wohl wieder auf Outlook umsteigen müssen.

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

Not working on 38.2.0 Rated 1 out of 5 stars

Cant make it work on TB 38.2.0!!!

Have tried several versions of Lightning (as per compatibility tables) but the only result is:
1) very slow startup, approx 30'' to 1 min
2) TB hangs frequently unreponsive, particularly after standby/suspend.
Tried everything, either to downgrade/upgrade TB to other versions, or to reinstall or remove/_recreate calendar links and/or calendar subscription, but the result is the same.
To me this could only be addressed with a better design project.
Hope this will finally work because that's the only reason to let me rethink my decision of moving to Outlook, or any other stable solution.

This review is for a previous version of the add-on ( 

Use 4.3b2 for SeaMonkey 2.38 Rated 4 out of 5 stars

Works fine for me so far, get it from (all the way down on this page).

Lightning releases are based on Thunderbird's 38.x schedule whereas SeaMonkey follows the general releases, hence a different (beta) version is needed for 6 out of 7 cycles. Would be nice if AMO eventually accommodates that.

This review is for a previous version of the add-on ( 

No longer works with latest SeaMonkey release Rated 4 out of 5 stars

I am a long-time user of Sunbird, so adoption of Lightning was a natural. I especially love the calendar file import feature that allows me to import calendar events downloaded from my children's school web site.

Alas, Lightning does not work in the latest release of Sunbird 2.38. Even the usual trick of editing the install.rdf file within Lightning's .xpi file to increase the SeaMonkey maxVersion parameter failed to work. I had to roll back to SeaMonkey 2.35 to restore Lightning. Looking forward to an update to Lightning soon that works with latest SeaMonkey release.

Actually, this problem highlights the primary reason I still use Sunbird even though it has been discontinued: it is a stand-alone app independent of any parent framework like Thunderbird or SeaMonkey but has almost all of the same features as Lightning.

This review is for a previous version of the add-on ( 

Great Job Rated 5 out of 5 stars

It´s an great add-on.

This review is for a previous version of the add-on ( 

Kalendereinstellung Rated 2 out of 5 stars

Ist es möglich den Montag als Wochenbeginn zu legen , nach der Aktualisierung ist es ja nun der Sonntag?

This review is for a previous version of the add-on ( 

Anscheinend handelt es sich um einen bug, dass nach der aktualisierung der Wochenbeginn auf Sonntag gesetzt wird. Umstellen lässt sich der Wochenbeginn in den Thunderbird-Einstellungen. Für Support-Anfragen bitte nicht die Reviews verwenden, sondern das Kommentarfeld auf der verlinkten Support-Seite.

problems with security Rated 1 out of 5 stars

i can not use Lightning because some sites are not accessable because Lightning. Disable Lightning and all sites are accessable. Activate Lightning and some sites back not accessable. I think it is problem with security settings of Lightning.

This review is for a previous version of the add-on ( 

An unfortunate combination, TB 38.2.0 and Lightning 4.0.2 Rated 4 out of 5 stars

Starting with the 4.x versions of Lightning, the extension messes up the settings I made. Whenever a server for a particular calendar is not reachable, it switches visibility off, readonly on, and lastly, switches the calendar OFF. This means I have to open calendar properties, switch calendar on, switch readonly off, save my settings, and tick the calendar visible. For each and every calendar many times a day, even if I only temporarily switch network connections.

I remember such behaviour back in 2011 when the "offline support" feature was not existing or in its early (experimental) stage. But now, as the offline support proved maturity, I cannot understand what rendered the offline support practically unusable.

It may be that the root cause is in TB 38 itself. I believe when I first saw this behaviour, I ignored it, thinking it would be temporary and soon be gone away. That's why I can only say: it started around the time when TB updated to 38, and Lightning updated to 4.x.

At the same time this behaviour started, TB started exposing a sluggish behaviour: from time to time (once per minute), TB suddenly starts using 100% of one cpu and becomes unresponsive for approx. 15 secs. I have then tried to switch off extensions until the behaviour went away. The critical extension was ThunderBirthday, and after some experimenting I found that the behaviour appeared only while one of my address books (LDAP) was not reachable network-wise.

As long as these problems aren't solved, I would not advise anyone to risk updating Thunderbird or Lightning to their latest versions. Previous versions worked nearly flawlessly for years, I could not imagine to live without these tools. I promise coming back and changing the rating when TB and Lightning find their way back to a stable productivity toolset.

Edit1: Prompt response, and with the fix ( the calendars remain enabled while the server is not reachable... Rating with four stars now, not for this version, but the overall completeness of this complex product.

Edit2: Spoke too soon regarding the spontaneus freezes. After the update of Lightning, they're there again, even without LDAP address books and ThunderBirthday.

This review is for a previous version of the add-on (4.0.2). 

The caldav switching off issue is known and will be fixed with which is already in review.

The cpu issue has been known for a while, and can also occur without Lightning. See for details. The detail with the LDAP addressbook could be a good data point. Maybe you could add it to the bug?

Lightning 4.0.2: Duplicates, Hangs, Server Changes Rated 1 out of 5 stars

I'm hoping that I'm using the wrong version of Lightning and that all my issues are solely compatibility errors. Otherwise, Lightning 4.0.2 is a disaster. It's difficult to post that comment because I'm very attached to its many good features, but the bad features far outweigh them. To those using only local calendars, this version may be acceptable.

I will modify this review if it turns out that I have the wrong version of Lightning installed.

I'm using Lightning 4.0.2 with Thunderbird 38.2.0 under Ubuntu 14.04. is my email and calendar provider.

Every time I reboot Lightning, Lightning forgets which calendars I had enabled. Once I select the Kolab (CalDav) calendar, I get many messages stating that changes have been made on the server. I'm asked if I'd like to override those. I'm never sure what the correct response to that question is because no changes have been made on the server since I last used Lightning.

Several years of calendar appointments now have up to 11 instances of a single appointment. For example, one such appointment occurs only once a year. Now I have 11 instances of it on that day. This has happened on hundreds of appointments.

This is a nightmare and will take me weeks or months to correct. I attempted to clean up this scheduling mess, but Lightning would hang or was so slow that I could only get 5 duplicate appointments deleted before moving on to another project. I would not recommend using the above combination of software/add-ons/services until this massive issue is resolved.

I've maintained an on-line calendar via client for 20 years without ever having experienced such an issue. I'm giving 1 star because Thunderbird has been a lifesaver to me in years past. I used to donate to the developer, but having my calendar in its current status is disabling professionally and personally.

EDIT: I updated to (Linux). Not only did the update not resolve the CalDAV shutting-off issue, it rendered the CalDAV calendars unusable. The CalDAV accounts are still added, but their appointments just don't show up. Thunderbird is still booting extremely slow with this add-on attached.

This review is for a previous version of the add-on (4.0.2). 

Good calendar, but occasionally troublesome Rated 4 out of 5 stars

Thunderb: 38, Lightning 4.02. --- I'm sad to say that recent troubles, including several hours of trying to work them out, have left me so frustrated with this addon that I've decided to uninstall it. I'm using Google Calendar, and the synchronisation has typically worked (mostly) well, but for unknown reasons it broke over the last few days, leaving me unable to alter anything whatsoever in the calendar within Thunderbird. Trying to start over by unsubscribing all calendar categories left me no better, as I couldn't re-add the calendar again as per the usual method - the line with adding (mygoogleemailadress) was gone. Apparently the 'cal still thinks my calendar is added to the program, yet it is invisible, and no preference panes or menu choices seem to allow me to wipe it out completely.

(In case this is an issue with the "google provider for Lightning" I apologize, though if I understand it correctly the developers are one and the same? In that case please work on a solution to display all calendars that are in store via Lightning, choices to reset them or wipe them out completely, and such.)

Apart from the Googlecal issues, the addone works well for local non-networked calendars and akaik, iCals.

*** Edit: The problem now seems to be with certain computers/Thunderbird installs only. Others work fine. I'll update this if there are any developments.

Edit 2: The problems have gone away after an uninstall+reinstall of both Lightning and the provider for Google Calendar plugin. I'm raising my review because of this, but will note that there has been a show-stopepr bug during use. ***

This review is for a previous version of the add-on (4.0.2). 

Good but upgrades usually end up breaking functionality Rated 3 out of 5 stars

Thunderbird - 38.2.0
Lightning 4.0.2
Provider for Google Cal 1.0.4

Invite emails are not being sent to invited attendees.

This review is for a previous version of the add-on (4.0.2).