iMessage not syncing across devices after macOS 26.0.1 update

I have had this same issue... this actually seemed to fix it for me:

1. Under Apps/Messages/Send & Receive on iPhone, unselect your phone number as a place to send and receive iMessages. You should only have your Apple ID/email address selected.

2. Turn off Apps/Messages/iMessage slider for 5 - 10 seconds. Just long enough for us to be sure it registered everywhere.

3. Turn iMessage back on. At this point you should only have your email address as the sender/recipient of iMessages.

4. Wait until you get the pop-up notification that (paraphrased) “your Apple ID is now being used for iMessage on a new iPhone”.

5. After you get the notification that your your Apple ID is now being used for iMessage on a new iPhone, you can change the iMessage settings to allow your phone number to send/receive iMessages again. Just don’t unselect the email address and only leave the phone number.

Found it here: https://forums.macrumors.com/threads/sms-messages-dont-propagate-their-read-status.2470463/post-34269593

I had a similar Messages sync issue on Macbook with latest OS 26, where the sync will just pause itself. Asking it to resume sync does nothing. I have plenty of disk space and I logged out/in of iCloud, reboot, etc. nothing seems to restart the sync process. Then, just for fun I plugged in the Macbook's charger (it had 76% battery charge so I didn't think it was necessary), but after 15 seconds on the charger, the sync started itself back up! So it seems that not being on a charger for iPhones & laptops might cause the Message sync process to pause itself until it's plugged back in.

I had synching issues and here's how I fixed it. On your phone go to Settings>Apps>Messages. Scroll down to Text Message Forwarding. Check to see if your devices are listed and selected.

Plugging in the charger didn't fix the problem on my mac os26. Apple is aware of the problem and issued a tech note to it's CS advisors acknowledging the issue and that they don't have a fix. Apple rushed the release of Tahoe because of it's AI enhancements, obviously with minimal concern that it might not be ready. I'm erasing my drive and re-installing Sequoia. This is a major gaffe and reflects the insane greed that drives bad decisions.

I'm starting to think my SMS unread message synchronization issue may not be related to iOS/iPadOS/WatchOS/MacOS 26, but maybe when I switched from an iPhone 14 Pro to an iPhone 17 Pro. I'm not sure. I finished upgrading everything to 26.2 and then sent a HELP message to an SMS short message service (Sonic restaurants if anyone is wondering), and I sent it from my Mac which immediately marked the response as read. My iPad and iPhone also received the response but did not mark the message as read. I went ahead and disabled Messages in iCloud on Mac/iPad/iPhone and then re-enabled it. The Mac and iPad are still now resynchronizing (I have years and years of Messages) so am not sure if that will fix the issue or not, but at least immediately after upgrading to 26.2, it didn't automatically fix it.

This latest update of Tahoe is horrible! Sometimes my iMessages will crash and other times it won't even open. The solvent is this...Open Finder, Shift+Command+G and you will see this come up...~/Library/Messages/. Click on the first search that comes up and you should then see files labeled, chat.db, chat.db-shm, and chat.db-wal. You will delete those files and then iMessages should open and work. If you've got iCloud backup on, then everything will filter back through and be restored, but it might take a while. I've had to do this numerous times having updated to Mac iOS Tahoe 26 and Mac iOS Tahoe 26.0.1. It sucks and I'm not sure why Apple hasn't come up with a fix yet. Very frustrating!

[Edited by Moderator]

yess!!! my MacBook Pro, iPhone, Apple Watch Ultra, iPad mini, iPad Pro all have a different number of “read“ blue dots and notification tallies. Had Apple Support on the phone and after a period of time the call was disconnected. I received a case ID via email and no fix. I had already tried everything, from removing VPN, to turning on the message sync on each device manually, restarting each device, signing out of iMessage and back in. And nothing helped.

Everything has been done and redone. Every device is listed and the account is chosen. I have turned messages on and off. I have restarted phones. I have restarted laptops. I have restarted iPads I have restarted watch. Nothing corrects this. And as far as I have searched, this is a known issue and there is no fix thus far.

@Artboy57 | This is what worked for me!

My desktop macOS had cloud storage of messages turned off for some reason, but even after enabling it ,it still did not work. Changing the setting on the phone is what made things start sync'n again.

My iMessage only goes to my laptop and I'm not getting messages on my Iphone. Some messages are missing. I did the software upgrade, but still the same issue. I have tried all methods to get it to work. I rely on this for employment and I'm missing jobs.

RCS and SMS look the same (green) in the Messages app. The way to tell the difference is that I see a case where I sent some SMS messages, and then when I received a response, it shows “Text Message - RCS” and the date/time before showing the message. On the iPhone, in the textbox to type the message it will also indicate RCS or SMS. What I notice on my iPad is that it says SMS, but when I sent a message from my iPad a few minutes ago, it still sent as RCS, but it always shows as green either way.

For me, it mostly seems to be SMS/RCS messages that don't sync correctly. I chat with my brother daily and he's on an Android phone. I constantly have "unread" messages on either my phone or my MacBook depending on which device I've most recently interacted with him on.

Thank you so much for posting this. I thought the problem was related to upgrading from an iPhone 14 Pro to a 17 Pro, but the subject line from MacRumors was exactly my problem. I went through the steps as listed, and then I have Google Voice through a GFiber home phone device, and I can text SMS from that phone number and was able to quickly verify that reading it on my phone marked it as read on my Mac, Apple Watch, and iPad. Having the iPhone and Apple Watch not even being in sync bothered me the most since the Watch is so dependent on the iPhone. It appears my problem is solved.

I still had something like 16 unread SMS messages on my iPad. Going through the procedure does not cause those SMS messages received before doing the procedure to suddenly pick up the read status from the phone. Those SMS messages will still need to be manually marked as read. It appears it only affects SMS messages going forward.

Thanks again to @dcmoody for finding and posting it. My issue appears to be resolved.

That is the exact issue that brought me here. I am hoping to find a solution soon.

similar problem here - sporadic syncing with macOS Tahoe, but it seems that only RCS messages are affected. Which should be a different color than SMS messages or iMessage messages, imho.