A co-worker of mine recently asked me why they could only leave certain iMessage conversations. I was intrigued by this question so I had to look further into it.
In case you didn’t know, you can leave an iMessage conversation by tapping on the iMessage thread> Tapping the group’s members at the top of the message >Tap the i for info> Scroll down to Leave this Conversation in red. If Leave this Conversation is greyed out, then you are in a iMessage group that cannot be left.
Why is this? It is quite simple. But if you didn’t know why, it might drive you crazy.
Any iMessage group that has three people or less in it, cannot be abandoned. For example, I cannot leave the group message between me, my wife and my mom. Now, once you add another person to that group, you will be able to leave the conversation.
So, to put it simply, three or less you’re stuck in the message. Four or more, you can get out the door.
Dad's Desk 