An Office 365 Exchange Online user had question about Group calendars in Office 365 and Outlook 2016. The user is sending invitations to the group and sometimes everyone receives the invitation while other times only some people get a copy. Note: this refers to the new Groups feature in Outlook 2016/Office 365 Exchange Online.
Group calendars invitations work pretty much the same way meeting invites to distribution lists work but because users can choose to receive email from the group, the group members might not receive all messages sent to the group.
If the meeting invites are not being distributed to all members who are subscribed to the group, you need to check the message trace logs in the Exchange admin portal.
When you create a meeting invitation in your calendar and invite the Group, you'll send the meeting invitations to the group and it will be distributed to the members of the group. This is similar to how it works with distribution lists, except the DL doesn't have a calendar.
When you create the meeting invitation in the group calendar directly, the group is the organizer. The meeting is added to the group calendar and all subscribed members of the group will receive a copy.
When you have a meeting already set up in the Outlook Group Calendar, and you add members to the group, and delete members, does it automatically send the new members a meeting invite for the meeting that is already set up, or do I need to resend invite. I also will delete members that changes out with other members, does the meeting stay on their calendar, although I have deleted them from the group? I just want to make sure when I add new members, it automatically shows up in their calendars, or they get something about the meeting when I add them. And if they are deleted from the group, the meeting is no longer on their calendar.
A colleague was complaining because Outlook/Exchange seems to send invites to all group members when a group calendar event has a location, even if she has unchecked the "Send invites to all team members" check box in OWA. I'm guessing it's because the room resource is technically an attendee with a calendar that needs to share updates, which makes the event a meeting, and meetings send invites. Is this just by design, or is there some kind of admin option that could be set to change this behavior? Thanks!
if she is changing the location, it will be sent to all attendees as the logic is they will need to know where its held. Time/Date changes also will be sent to all attendees.
How many ad groups can you add in one calendar invite?
Any limitation in calendar invites will be the same limitations for sending email to groups.
If it is an Exchange group in the GAL, each group = 1 attendee. (The Exchange admin may limit the number of attendees.)
If its a Contact group in Outlook, the group expands before sending (attendees = number of group members) and you will be limited, either by your SMTP server (if it limits how many people you can send to in one message) or because the addresses exceed the length allowed in the To field (I think it's around 1024 characters).