Q: Messages says "XXXXX is not registered with iMessage"

Hi,

Did anything change those "two Days ago" ?

New router ?

Change in Time Zone ?

Change in Date Settings ?

Has your ISP changed DNS servers ?

9:09 pm      Tuesday; July 22, 2014

No, it's all the same.

Hi,

If you don't have one already can you go to System Preferences > Users and Groups  and create a "test" account.

Can you then login as that test Mac User account and set up the iMessages account with the same Apple ID ?

Does it work in this Mac User Account ?

This will tell you whether it is the App (fails in both Mac User Accounts) or just your regular/everyday account  (it will work in the Test account but not in yours)

9:45 pm      Tuesday; July 22, 2014

I did it all of this and still nothing happened. Again, this red light (in the name of the contact) and the same message appears.

HI,

If you are saying the app dis not work in another Mac User Account then Reinstall the OS.

7:19 pm      Wednesday; July 23, 2014

I am having the same issues on my Mac.

I have tried:

1. delete all four .plist files Ralph mentioned in this and another threads

2. reset Key Chain

3. log on iMessage with a different Apple ID

4. did the above all together and restart my computer

Unfortunately none worked.

It used to work just fine.

Now everyone contact in my chat window is in red.  

Me too, I've even tried to reinstall the whole system but I can't even send imessage right after I get in the new system!

It used to work perfectly fine but one day it stopped and tell me xxxxx is not registered with imessage even if they totally are.

I'm using a 2014 Macbook Pro 15 retina with the latest OSX Mavericks 10.9.4.

It has been awhile now, do they (Apple) know about this?

Wait, you did a format to your Macbook, reinstall mavericks and still having this problem?

I am asking because a friend of mine offered to format my own Macbook tomorrow.

HI,

Have you tried restarting your computer holding down the CMD+ALT+P+R keys until you have heard two extra Start up Bongs ? (PRAM/NVRAM reset).

7:47 pm      Thursday; July 31, 2014

Hi,

Reformat and Reinstall would remove all the Mac User info as well.

At this point, before adding back any Mac user via Time Machine or other method the system should be vanilla as they say and you could try the Guest account  (Most likely it will insist you create a Mac User account first).

Just Reinstalling leaves the Mac User info where it is.

Most likely if the app is starting up but then cannot tell you if you Contacts can receive Messages  (how the app tells you is not actually clear) tends to mean your version is not logging in fully.

The Why of this is the difficult bit to  work out.

However reinstalling by whichever method and adding back the User's info is likely to recreate the issue.

The most common issues are:-

The DNS servers being used cannot find the iMessages Servers.  (this was more common with Messages beta than now)

The Date and Time being "off" particularly if out of sync with the router.

The Serial Number of the computer is needed before you get this far.

You can lose contact with the server and then the .plists involved have info that is not longer valid and it will not reconnect properly.

The iMessages account needs the font AppleGothic.ttf to be present and working properly. It uses this fro the "Registration" of the Apple ID - which it then seems to re-do at each start up of the app.  (this does make some sense as when you take an iPhone Off line such as Airplane Mode the Messagesa app there re-registers the iPhone Number.)

There can be an issue if the country in Messages > Preferences > Accounts > iMessages account > Details Button is not correct.

8:07 pm      Thursday; July 31, 2014

That's right, I reformat and reinstalled OSX Mavericks. And the first thing I tried is the message and it's not working.

It looks like an account problem to me. At least it should be some server problems that caused all this.

I still don't know how to fix it but I don't think DNS does anything to do with it. I can sign off and sign in, and I can check account details. That means the DNS server should be working, right

And I have some i-devices and macs. imessage works on all my ipad and iphones but not on macs. I tend to believe that it's caused by one mavericks system update because they all work until recently. all my macs are affected.

HI,

How are you getting to the point where the Mac has Mac User accounts again ?

Are you migrating old accounts back to the fresh Install ?

Or are you setting up the Mac with a new Admin account and trying Messages there ?

There are two thing the Mac MUST have to allow the iMessages account to work.

The first is the Mac Serial Number must be readable by the system.

Use the Apple Icon top left > About this Mac. Click twice on the line that tell you the current OS level.

This will change to the Build Number and then to the Serial Number.

The second is the Font AppleGothic.ttf

This is found in Hard Drive Name/Library/Fonts

You can check it with the Font Book (Here it appears near the Bottom of the list)

It should Validate and be On.

Others have found that in the Finder window, they created a copy (Duplicate in the file Menu of the Finder) and deleting the Original and also as a separate thing moving it to Hard Drive/System/Library/Fonts which is the normal place for Fonts used by Apple Apps and the System.

All the account that can be set up in Messages on the Mac require that the computer is set to a Date and Time Zone as the Messages fro all these services are time stamped.

In Addition the iMessages account needs it to be in place and set before the iMessages account is set up.

If the router is set to a different Time (lack of Daylight Saving Times for instance) then there can be issues with that.

If you have iOS devices that are logged in to Messages using the same Apple ID then the issue is not with the iMessages account itself.

It is either with settings on the Mac itself or it is something about the Mac User Account being used.

9:11 pm      Friday; August 1, 2014

I already did a clean install of the os x, and i check also all of the thing you said Ralph and the are correct. I'm gonna contact with the apple store service from where i had bought it. It's my last option...

Understood.

8:44 pm      Saturday; August 2, 2014