Why is iMessage combining two contacts into one thread. I can only text back the last one that messaged me. This started with iOS 12

No. It's not. In EVERY case, the root cause can be traced to the sharing of iCloud accounts. Signing out of the accounts alone didn't fix it because you'd already borked things by sharing IDs in the first place. The fix has been documented here already. You choose to ignore it, you live with the problem.

It is unfortunate that people have to come into a discussion such as this one and would rather be self-righteous than helpful or understanding. Whether or not Family Sharing is available as an option and has been encouraged by Apple, the fact remains that Apple knows people do still share Apple IDs, this iOS update has created a lot of headaches for a lot of people, and no one seems to have any solutions besides restoring your phone and potentially losing years and years of data. Understandably, most of us don't think that is a feasible solution.

It's unfortunate that people don't understand that smart phones, tablets, and computers are machines. They do what they are told to do. When you ignore the instructions for operating them, you open up a Pandora's box filled with chaos.

Perhaps you've heard the term "garbage in, garbage out"...? It may very well pre-date you, but you would be wise to look it up and at least try to understand what it means.

What we have here is a clear case of "garbage in".

How is this turning into an idiotic flame war?!! The bottom line is that Apple made an assumption that grouping conversation threads by Apple ID would better organize things. I suppose they didn't realize how often people/ families share these ID's, so they didn't see this mess coming. It is not a bug. It is intended as a feature. If you do not like the change, you need to post info to that effect on Apple's feedback page, not here. There are only users here.

donnym2007 wrote:

Not true. Most families, especially with small children, do indeed share.

That is what Family Sharing is specifically designed for. And, how do you know that "most families" do share? Where did you get that data?

I am having this issue as well, since I upgraded to IOS 12 last week on my iPhone 8. I have removed my husband and my son as contacts and reentered them again; I have turned off iMessage and turned it back on again; I have tried the different apple ID's on three phones and nothing is working. It works for a couple of days and then goes back to having the one conversation for both my husband and son. It is frustrating! 😠 I then have to delete the message and individually wait for them to send me a text again and it starts over again. Annoying!!

I was going to go down to the Genius Bar tomorrow but it sounds like that would just be a waste of fuel and time...

If you read my posts on page two, you will see that you are, in fact, in correct. I have my own Apple ID as do each of my parents. Yet for some reason, their threads continue to merge on my phone. Mine aren’t merging on theirs, but theirs on mine only. The only way I can fix this, and this fix is temporary, is to delete their threads and start over each time they merge, which is multiple times per day. So, yeah, iOS 12 is bugging, and it’s not because I don’t know how to use an Apple ID.

It is irrelevant whether most families share or not. They should be using the system in the way it was designed to be used, with Family Sharing. Piling everyone onto a single Apple ID is unsupported, has always been unsupported, and has been causing random and unpredictable problems for a considerable time. Over in the Apple Watch communities we also have a similar issue ongoing with Activity data and awards getting corrupted and cross linked between two sharing users.

We were having the same issue. This fixed it. Try this on all devices that are included. The person that was having the trouble sending texts to the wrong contact was not the one that had to fix their phone setting. It was actually one of the recepients.

delete the iMessage threads that are being combined.

Go to settings,

Apple ID ,

icloud,

go to end of page - share my location. Make sure only your device is checked.

Then send a new thread to each person separately to confirm it was fixed.

I have the same problem with my mother and sister. Their contacts merge, and I can only message the last one to message me. If I type the name of the other person into iMessage, it showd the messages of the last to message me (either my mother or sister). Very upset, please resolve Apple!

The only way I was able to get this to stop was assign one email/phone number to iMessages. I did this both on my end on the people I was contacting. My SIL was receiving the messages I was sending to my brother. I was perplexed. took me a few hours to sort out what was happening. I wiped this down to using only one email/phone number in my settings.
Which, as someone pointed out, this is assigned to one apple id... I think this is the problem i was experiencing, not sure.
I sent them messages using iPad, iPhone and MBP, then asked them what email/phone number the received it as.

Anyway, now I am afraid to selected all my emails I can be reached at because it may return to this craziness... I will follow threads to see what happens.

Most people are using it as it was designed to be. That's why each device has a "send and receive" section on it so they can pick what each phone receives. Even if one person only uses one id this is a issue. Say you have a separate work and personal phone signed into your apple id, now it's screwing up those messages and not separating them.

Apple, please help! iOS 12 has completely ruined my iMessage! Texts to my husband are going to my kids and vice versa! Im assuming its because they all have the same home phone, iMessage thinks theyre all the same.

The really strange part is that it selectively chooses which of the four of them to text each time! And it seems to change to a different child at random ; meanwhile important text messages arent being received by the proper party and its messing up my life! Please help quickly!

After reading about iMessages, I'm taking a stab at this solution.

Go into each device, log in using Apple ID. This might be where everyone is losing control. Determine if you want to use your own ID or shared ID.
Go to settings on iOS devices and to Messages (and really should do the same for FaceTime)
Reset can be reached at and messages sent from.
In some cases might have to log out and back into iCloud to effect change.

In OS open iMessages, Preferences, Accounts and make the same changes

Make sure all devices have the same phone/address selected in each (if that's how you want it to work)

This is what I did (on the latest iOS 11). I am only thinking when iOS was installed it kicked out these settings or defaulted to something else.

I had the same issue, which I have now resolved:

Go to Settings/ Messages/Send and Recieve

Touch on your Apple ID and sign out from your Apple ID for iMessages.

This will enable all devices to use their phone numbers only for messaging and not merge messages with the same ID.

Then delete the threads where the messages have merged and start again. It works for me.