iMessages not syncing on latest OS

I have solved it for myself. Have High Sierra, iPhoneX and iPad Pro. Not synching where they formerly did - before I got the X. Kept trying the solutions below on my Mac with no luck. Then I thought to change my phone settings. Went into settings and imessage. Flipped it off and then back on. signed back in with my Apple ID. Then on my iPad and Mac I got a message asking if ok to synch with my phone. Done!

Hi,

No doubt you have this sorted out by now but in case someone else experiences this problem; I had this problem but the solution was to go to my iPhone's Settings->Messages->Send & Receive and add my my Apple ID. It only had the mobile phone number in there.

Hope that helps someone else.

Mark

Try removing the account in Messages > Preferences > Accounts then add it back. Removing an account then adding back has fixed similar issues for account that failed to sync in Mail.

Sign out. Quit Messages.

Go to your User's Library > Messages

Rename to MessagesXXX

Open Messages

Sign in

Does this help?

I disabled location services on my mac and that instantly fixed the issue for me. Not sure if this will work for everyone but might as well try to help.

Not sure if this is still live, but i got here via a search so perhaps this might help others. The trick for me was:

ON THE PHONE - Setting > Messages > Text Message Forwarding > Select the new laptop.

Boom.... everything works.

Sync has always been difficult. Since Messages sync is new, I suspect it will take some time to work out all the kinks. Messages.app on El Capitan will never sync. Only Messages.app on High Sierra will have sync capability.

Since you have an iPhone X, you are elligible to Apple support. I would call support and see what they recommend. If they do provide a solution, please post back here.

Contact sync is also having issues at this time. Some users have had to first save all their data then remove from all devices including cache files before sync starts working again.

A possibity to start fresh on all devices is to first use a third party product that will save all data off your iOS devices.

Start by testing out the demo on iExplorer. It's simple to use and you can see what it can recover. Data is in a format you can read without having to import back into your device.

iPhone Music, Messages & File Transfer for Mac & PC · iExplorer

How to back up your iPhone, iPad, and iPod touch - Apple Support

Hi,

Open/Launch Messages.

Use the App Menu > Preferences

Select the Account pane icon.

Select iMessages if you need to.

Use the Sign Out button top right.

IF you Quit and reopen Messages and return to the same spot then your previous used ID still shows but the Password but should be blank.

You can overwrite the ID part and enter a new password.

8:41 pm Wednesday; February 7, 2018

In lieu of creating a new thread about this issue, I'll just post some observations here. I, too, am having this issue with Messages on the desktop. I'll receive a message to my Apple ID on the iPhone and my Messages.app on the desktop stays quiet. I'll type out a reply on the desktop and it takes 30 - 90 seconds for the message to be delivered. There's a progress bar at the top that moves and pauses numerous times throughout the process. Messages.app reports the message as delivered, then, within the next 10 - 20 seconds, the app refreshes with a flurry of messages that weren't synced.

At this point, there appears to be a connection with the server as messages flow to both devices, as they should. When the timing of sent and received messages slows, the Messages.app on the desktop appears to drop the connection. New messages arrive on the phone but the desktop lags. Sending a message from the desktop restarts the process again (slow delivery, delivered, old messages sync).

It's an easily reproduced pattern.

I've tried numerous things to resolve the matter, including deleting all devices from my apple id, turning iMessage on/off on all devices, deleting old messages, deleting accounts, preferences, iChat prefs, etc. Nothing has worked for me.

Looking in console.app, there's quite a bit of activity for Messages, imagent, identityservicesd, and others.

Frustrating, indeed.

This helped me. It was not an immediate fix - It took 3-5 minutes to sync up after I opened Messages for the first time after renaming to Messages XXX. But now my iOS devices and my MacBook Pro are happily syncing.

Thanks for the feedback. When you xx out a folder for testing, you can always remove the xxxs to go back to the original. In your situation, since it fixed the problem, you can now delete the old folder.

I'm having this problem too

I purchased an open box Mac Dec 7. Wasn't sure if I would keep it. When I set up. I clicked no thru everything. I intentionally didn't want anything to sync. And of course it did! FaceTime & messages (all message history) But since I clicked no to everything at initial setup/install. I decided to do a factory reset (actually the store that I purchased from did it). Second time round setting it up with the intention to have everything sync. Funny though this time during the initial set up I was never asked if I wanted to sync everything all I had to do was pick my language, click yes or no if I wanted to step verification, sign in with my account password that's about it. There was no asking to sync devices. And of course now nothing will sync. I understand the operating system and the interface. I know & understand how to set up syncing and text forwarding. I have done all the fixes that I know of as well as the ones on the Internet. And I still cannot get my iMessages to sync the history. All the imessages sync that were created after setup. But my previous message history won't. However all my FaceTime history has synced.

The store gave me a brand new MacBook (stellar warranty!) and same thing happened during setup and iMessage history won't sync! I think the open box MacBook prior to the factory reset was in an older macOS cuz everytime since then it won't sync iMessage - was able to fix the FaceTime history to sync this time around tho.

So frustrating. Pretty sure I'm gonna return this til Apple gets it together.

Annoyed x 10!

Messages sync is new and was not even included when High Sierra was first released. If you are trying to get messages from a previous macOS, you would need to manually bring over those files.

https://9to5mac.com/2017/10/18/imessage-icloud-sync/

https://www.macrumors.com/2017/10/18/macos-high-sierra-users-delays-receiving-im essages/