I'm using Thunderbird 12.0.1 with the following add-ons for the calendar:

  • Lightning 1.4
  • Provider for Google calendar 0.9

I'm working with Ubuntu 12.04

When I receive an event invitation from Outlook or Gmail, the mail is correctly identified by Thunderbird (I have the message "this message contains an invitation to an event"). In the pretty little box in the mail (the one which contains all the details), there is no "Accept" or "Decline" button.

I found on the Lightning forum that this bug was fixed in Lightning V.1.0b2.

So, why am I still experiencing this bug?

10 Answers 10


I use a Google Calendar with Thunderbird/Lightning and I have always been able to Accept invitations through Thunderbird.

I recently lost the Accept/Decline buttons and just figured out the problem. I had recently added a shared iCloud calendar, and the new calendar was automatically associated with the same email address as the Google calendar.

All I had to do is set the iCloud calendar to not be associated with my email address, and my Accept/Decline buttons came back.

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  • Did the trick. I added a bunch of calendars to Thunderbird and it associated all of them to one of my email accounts. I associated one email with one calendar, another calendar with another email account, and the rest of the calendars with "None". Worked :) – djhaskin987 Feb 11 '15 at 21:10
  • how do you remove the association? – Tim Abell May 10 '16 at 13:01

I've suffered the same symptoms but with the following configuration:

  • Windows 7 Enterprise
  • Thunderbird 24.5.0
  • Lightning 2.6.5
  • No Google Calendar plug-in
  • A few webcal calendars plus a couple of local moz-storage-calendar calendars

After a few wild goose chases, this solved it for me:

  1. For all non-editable calendars, change Properties->Email to "None"
  2. For all editable calendars, set Properties->Email to your email account.

Boom, buttons suddenly appear. For me it seemed that have a Read Only calendar with an email set was preventing the buttons from appearing. I'm not sure what the trigger was - one day it was working then it wasn't. Nothing relevant appears in the error console.

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In the current version (0.18 with lightning 1.9.1), this is a hidden feature which is disabled by default. It is slightly buggy, but works sufficiently to just get an invitation into your google calendar from your (possibly non-google) inbox.

Using the config editor, simply set calendar.google.enableEmailInvitations to true. You may also want to set calendar.google.sendEventNotifications to false to avoid the possibility of an old bug that sent new events instead of notifications; I've not tested this. Then, restart thunderbird.

Once you have done this, in the properties of your google calendar, you will have the option to associate it with an account.

If it still does not work, try deleting and reconnecting your calendar via the xml-address from the Google Calendar website.

After you do that, you will get the appropriate buttons (they will appear with a brief delay as your google calendar is checked to see if the event exists). If it doesn't, you can use the accept/decline/tentative buttons as with other calendar types.

One bug that currently exists is that if the event is in your calendar already, you will get an update button whether there is any change or not. The button will usually cause an error if pushed.

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  • 3
    I'm such a newbie I needed this link: support.mozillamessaging.com/en-US/kb/… for "how to get to the config editor" Hope it helps someone. – FlipMcF Aug 16 '13 at 22:59
  • Enabling calendar.google.enableEmailInvitations solved it for me, didn't encounter an update button yet, so no information about it. – DBX12 Feb 11 '17 at 11:18

Here is my work-around using Thunderbird 17.0.4, Lightning 1.9.1, and Provider 0.18. Double click on the invite so it is in its own tab. Right click on the email invite and a sub-menu appears. Select 'Convert to' and then a smaller sub menu window appears with "Google task", "Event", or "Task".

Select "Event" and it will place the details of the invite as a new appointment in your Google Calendar. The click ok.

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According to multiple threads I've found, Google cal does not support "Accept" or "Reject" somehow. http://forums.mozillazine.org/viewtopic.php?f=46&t=1826045

The solution was to set the "Automatically add invitations to my calendar" option, but it doesn't say whether on gmail or in lightning.

Just found a solution for me (not-a-google-calendar) - the calendar has to be associated with the email!

The "display attachments inline" option seems to be irrelevant in my versions - TB 16.0.1 , Lightning 1.8

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  • The second link now goes to a page with "Quotes by Steve Pershing", fwiw. – ruffin Jan 29 '15 at 13:39
  • second link removed – Rbjz Jan 29 '15 at 14:38
  • I finally found a hidden preference that allow for just that. See superuser.com/a/1392185/13818 – Natim Jan 9 '19 at 8:38

Here is my work-around using Thunderbird and Lightining. I read/write google calendar through CalDAV https://support.google.com/calendar/answer/99358?hl=it I think that is the only way to bind the email with google calendar. So, when you receive an ics attachment, you can Accept/Decline invitation on your google calendar. Hope it helps.

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I tried adding my calendar using ics, caldav several times and was unable to do so as the calendar was unwriteable. This meant I could not accept invitations. What I found was that if I added the google calendar, then exited thunderbird, then restarted thunderbird I was prompted to upgrade the newly added calendar to a writable calendar. When I did the upgrade, everything works great. Lightning now reads and write to my google calendar account and the accept, decline, ignore buttons work perfectly.

Additionally, I had to add Providor for Google Calendar 0.25 to get the accept, decline, ignore buttons to appear.

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This article has a few useful hints and helped me fix the issue of no accept button.

Simple create a new network calendar with URL: https://apidata.googleusercontent.com/caldav/v2/your-email-address/events

Replace: your-email-address with your @googlemail.com address. Make sure it's @googlemail.com and not @gmail.com

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Using Google Calendar Provider, by default e-mail invitations are deactivated.

You can use this solution to fix it.


  • Open Preferences -> Advanced
  • Edit configuration and search for key calendar.google.enableEmailInvitations
  • Set it to true
  • Restart Thunderbird
  • Right click on your primary calendar and select the email address to use.
  • You can now accept email invitations and pick the calendar you want.
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Under Properties for your google calendar, enable the email address associated with your google calendar.

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