My texts in the Messages app have not been syncing between all my devices for a while now. I could not figure why that was until I did a little research online. If you are having this issue, then read on for a very simple solution.
Here is what you need to do to fix this issue. This all assumes your Messages phone numbers and email addresses on all your iOS devices match your Mac. Message Syncing all comes down to your iPhone. Go into the Settings area of your iPhone, scroll down and tap on “Messages:”
From inside the Messages app setting scroll down to and tap on “Text Message Forwarding:”
You will be taken to this screen:
As you can see Text Message Forwarding for my iPad (grayed out) and my iMac is turned off. Just tap on whatever is turn off to activate it and you are done:
Once I activated my iPad and iMac all of my texts in Messages were synced. Since I do a lot of work on my Mac during the day, this will be very convenient.
If you are missing texts on some of your devices, the Text Message Forwarding area is the first place to check.