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

I agree. It affects people who share Apple ID's and the people who simply communicate with them. As you state about the (forced) merged thread. My experience is that it's randomly selecting the person (not just the last person who messaged you). For instance, on my phone if I'm texting John and my phone shows John, my message is actually sent to Sue. Even though the last message i received came from John, but new message was delivered to Sue.

I believe the issues are interconnected and I agree it's caused by people who share Apple ID's but the problem is still that I cannot control how people use their Apple ID's and now I cannot trust my phone when it says that I am messaging a particular person. IMO Apple has delivered a fatal blow to their iMessage App by making it unreliable. How can I know if I message someone new and they happen to share an ID with someone that my message is going to the correct person? I have no way of knowing if they share their Apple ID or not. Apple needs to respect the settings people have on their devices and not link these numbers on their servers.

Refraining from getting involved in the whole shared Apple ID vs. Family Sharing issue here, because I am over it, I would also say that even just sharing an Apple ID from my iPhone to iPad has caused issues, and I don't believe Apple has any sort of edict that we need to have unique Apple IDs for our iPads as well (unless I missed that particular memo.) Further, as other people have stated, some people have two phones (one for work, one for personal use) with one Apple ID, which is also causing merging problems.

I think your last sentence says it all - Apple has settings for send/receive and start conversations from, but they are not respecting those settings. While in some cases I see the advantage of merging conversations (whatever the intended purpose was to begin with), I think not giving consumers the right to opt out of a forced merge was short-sighted. I can only hope that with Forbes and Mashable picking up on the issue, some sort of fix (or even a rollback) is in the works.

I, also, share your reluctance to bring up the shared ID and Family Sharing issue. Honestly, it's none of my business how other people use their Apple ID's. It's only become my business because Apple is merging years of messaging history into one unified thread. Something I should have been asked for. My biggest concern here is that it has made iMessage unreliable.

Creating separate Apple ID's and Family sharing is not a solution as it still leaves iMessage broken. Unless Apple makes all users do this unilaterally and immediately.

For my issue, I am not the one sharing an Apple ID and I cannot make other people get their own Apple ID's. Until Apple creates a solution which either fixes the problem or forces other users to not share their ID's, I cannot be certain who is messaging me or who I am messaging. This leaves iMessage completely unreliable - if the receiving party fails to properly set up their Apple ID you cannot be certain of the recipient. This would even be true of new users setting up new accounts. If they share an ID you may inadvertently message the wrong person and you would have no way of knowing.

I am having the same issue. My daughters and I share an iTunes account (Apple made this option available). Everything worked perfectly before I upgraded my OS. Now, I can only text whichever daughter texted me last. Help Apple! This is a mess.

I am having the same problem. I updated to iOS 12 a few days ago but today my dad’s and sister’s contact merged into one thread. My dad uses his phone number on an iPhone and my sister uses an email on an iPad to send iMessages. None of their contact information is the same in my contacts (they don’t share a common email or phone number.) They are both on the same Apple ID, however I am on a seperate one (under theirs with family sharing) and neither have updated to iOS 12 yet. (My dad is on iOS 11.2.6, sister is on iOS 9.3.5) I tried restarting my phone but that made no difference. I deleted the combined thread and asked them both to text me. It showed up as two different threads as normal but soon after it combined again.

This problem was driving me crazy too — but I think I’ve found a solution: Turn off iCloud backup (Settings > iCloud > iCloud Backup > Off).

I had tried setting up separate Apple IDs but that didn’t solve the problem — was still getting merged threads from my family. I had gotten OS12 a while ago (not Beta) but had not had this problem until I turned iCloud backup on — which required changing the toggle on the phone, not just in iTunes.

Hope that helps people. Still a major bug as far as I’m concerned.

Wesley is correct. From what I've read from other threads, Apple makes this connection on their server. There is nothing we can do but wait for Apple to fix it. Turning off iMessage hasn't been a solution for others on this thread either.

Turning off your icloud backup is just going to leave you without a backup should anything ever happen to your phone.

My son and daughter-in-law are the only ones I have this issue with. I have deleted their contacts and then deleted the iMessage threads that we had going. Then added the contacts back in. Two hours with AppleCare this morning and all was going well. Then tonight, same issue. Tried sending a message to both or either, and they only show up under my daughter-law’s name, all grouped in same thread though messages were sent separately to each. Is this a bug in iOS 12?

LaurieB wrote:

[snip]…

Is this a bug in iOS 12?

Nobody is sure until Apple investigates, creates and tests a resolution, and rolls it out. It could be a bug, or it could be the result of fixing a bug.

If there was a broken feature which until now allowed users to do something unsupported and in violation of Apple’s design because the function didn’t work, should it be fixed so it works according to the blueprint and enables onward development of new features but that fix causes problems for a small minority of users? Or should the bug be written into the product architecture and future development stopped?

An update for anyone following; I contacted Apple support and explained my situation. That two people that I know share an Apple ID and it has caused problems on my phone and not theirs. Their recommendation to me was - those people are going to see this problem more and more as people update their IOS and that they really shouldn't share an Apple ID. I explained that I didn't have any control over how they used their Apple ID's and my phone is the one being changed. Then they recommended - and I kid you not - that I disable iMessage on all my devises.

It's really not a problem for me.... Bye-bye iMessage.

The thing is, I disabled iMessage during this whole mess (on all devices) and it did not solve the problem; in fact, it created the (much worse) problem that I did not receive texts from anyone texting me using iMessage, so I had to turn it back on. Not only does Apple's advice make no sense logically, it isn't even a solution.

This is so dangerous! I have a suicidal teenager and I am his lifeline if he needs me. Since we updated 2 days ago, even if I type in his number directly or he types in mine my youngest son is the only one to receive the texts. It is unsafe for my oldest and unfair for my youngest to have the pressure and responsibilty. I have tried reaching out to Apple and nothing. The anxiety it is causing our family is off the charts.

I am having the same issue. My sons are both getting the same text from me. I can’t sepertae their messages. I have no idea who is getting the text. This is infuriating. I gave never had this much of an issue before.

Having same issue since updated. Talk with senior adviser for 1.5 hours on Monday. Thought it was fixed. Two hours later messages merged (?) again... they did a follow up call today. Let them know it was still happening... . They are telling me it is due to more then one person using the same Apple ID.

I am the only one that text this family member that is having the issue. Very concerned that it will happen with other people I texted with. The text I send to my son is going to my daughter in law ????