iMessage not synching between devices

[vbmike73]

My iPhone 6 and my iMac running Yosemite synch fine together. And I have the SMS forwarding on so non-iMessage texts go to my iMac. All is good.

But my MacBook running Mountain Lion acts very weird. It takes forever to synch, and when it does, some threads are missing messages. Some of the threads are totally out of order. Text from last night appearing after text from this morning. Doesn't make any sense. And my MacBook does not get any of the SMS texts. Maybe I can't forward SMS to more than one mac? Is this why it's not synching on the MacBook perfectly? Or does it have something to do with the iMac running a newer OS? Can anyone shed some light on this? I blocked all content on my Flash Player as suggested by another thread from 2013, but it's not fixing anything.

 

[Kissmyne]

My iPhone 6 and my iMac running Yosemite synch fine together. And I have the SMS forwarding on so non-iMessage texts go to my iMac. All is good.

But my MacBook running Mountain Lion acts very weird. It takes forever to synch, and when it does, some threads are missing messages. Some of the threads are totally out of order. Text from last night appearing after text from this morning. Doesn't make any sense. And my MacBook does not get any of the SMS texts. Maybe I can't forward SMS to more than one mac? Is this why it's not synching on the MacBook perfectly? Or does it have something to do with the iMac running a newer OS? Can anyone shed some light on this? I blocked all content on my Flash Player as suggested by another thread from 2013, but it's not fixing anything.

1. You CAN forward messages to more than one device(Mac, iPad.. etc)

2. SMS Forwarding requires OS X Yosemite(10.10) or newer.. update your Macbook and all will work as you are expecting..

 

[jeyf]

i had issues with the Messages app un related to the OP but:
-on an old macBook Pro i was unable to get messages to connect to the mighty iCloud. It wold give an error message to call home to the apple mother ship gave a phone# & id# for that purpose. Odd. It took 6.66 phone calls to find a sit where they knew what was going on. The case# got elevated a lot and finally one day it started to work.
-i think, from what i read on macRumors if you go from say 10.8 -> Yosemite and fall back to 10.8 the db locally and or front end at apple.com gets confused. Use caution but locally you can consider deleting ~/libraries/messages on your macBook. For me this didnt help tho.
-even if you do not have apple support for your hardware device (macBook Pro) apple allows you to call in to phone support for iCloud support. Maybe in a totally none accusing way apple know there is iCloud gate issues. So take advantage of the free voice phone support. Re join the 90s