Now when I am testing this I set up a date with attendees and with a reminder 24 hours prior.

The appointment will be added to your calendar, and you'll get a reminder for it 24 hours prior. This isn't a reminder to re-send the invitation.

When I save it, it asks me immediately if I want to send an invitation now...I click no

You'll have to say 'yes' to send the invitation in the first place. If you say 'no', the invitation is never sent.

assuming it will send the message 24 hours before the meeting.

You can only send the invitation immediately. I don't think the functionality for delayed sending exists at all.

Thank you for the clarification. Unfortunately the use of the word "notify" and "notification" is very inconsistent among programs.

Now at least I know that I cannot do what I was hoping to do.

It is most unfortunate that no program (as far as I can tell) has the feature which would allow setting up meetings on a calendar and then sending "reminders" at a predetermined time.

There is no point in setting up a meeting for next month and sending a notice now, without sending a reminder closer to the meeting date.

Maybe TB could add that feature.

Thanks again.

When you send an invitation for a meeting for next month it is up to the recipient to set a reminder for the appointment.

I appreciate that...but we all know the reality.

I think it is great that my dentist's and doctor's office call me with a reminder about an appointment in two days' time, even though I have put it on my computer's calendar.

I am looking for a similar feature on a calendar.

Sending reminders is problematic.

If we were to use Thunderbird/Lightning then it would need to be running and connected to the internet at the precise time at which you wanted the reminder sent.

We need some sort of online resource to do this for us; a server that is kept running 24/7 with backup and failover. Or a self-contained device such as a mobile phone.