https://support.mozilla.org/kb/using-lightning-calendar-add-on

Christ1 - show me exactly where I can execute a command or select an option which makes my Lightning "writeable". My preferences already have unchecked "read only".

Please provide more details about your environment.

• what calendar(s) - local or network?
• if network - is this a Google Calendar?
• if Google - how do you access it? Via the provider add-on or CalDAV?
• have you assigned the correct email address to the calendar, i.e. the one the invitation is sent to?

• Network (private one PC) syncs with Google Calendar, same account as gmail account
• access via googleapi://.................
• (Not Cal DAV)
• correct email assignment

When I open the email invite in my Gmail account (which is synced to Thunderbird/lightning) the invite has the buttons for selection (Yes, no, maybe). If I select yes it transfers to my Google calendar, then Google calendar syncs with Lightning and shows accepted invite.

However, if I first open email invite in Thunderbird, above the email header is message " No writable calendars are configured for invitations, please check the calendar properties" and the selection buttons do not appear in the email as they do in gmail (yes, no, maybe).

So can Lightning be made writeable for invites or am i just wasting my time? Thanks for your efforts.

A Google Calendar set up in Lightning should be writable anyway, otherwise it would be pretty useless.

You can try to delete the Google Calendar in Lightning, restart Thunderbird, and set up the Google Calendar again.

Check if that makes any difference.

Thanks for suggestion. For now I don't plan to delete and re-install. I do have Mozz back up but i don't think re-install will address issue. Maybe some day in future when i have more time i will try delete/re-install. There are a few other "write" quirks which occur between Lightning and Google calendar and I live with them and do workarounds. I have received Outlook invites and they work OK within Lightning. I need to find out from which program the "problem" invite originated to determine what might have occurred. I will mark this as "solved". Thanks for your input.