Can not sign into iMessages on my profile

Might be a corrupt .plist.

Do a backup, preferably 2 backups on 2 separate drives.

Quit the application.

Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J. When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder. Select Library. Then go to Preferences/com.apple.iChat.plist. Move the .plist to your desktop.

Restart the computer, open the application and test. If it works okay, delete the plist from the desktop.

If the application is the same, return the .plist to where you got it from, overwriting the newer one.

If that doesn’t work, repeat the above but delete the com.apple.imagent.plist

Thanks to leonie and Ralph Johns (UK)for some information contained in this.

Hi,

Can you go to ~/Library/Preferences (Normally holding down the ALT key whilst using the Go Menu in the Finder allows you to access the ~/Library as it appears in the Menu list) ?

In Mountain Lion you should have two .plists with the word iMessages in them

com.apple.iMessages.bag.plist and

com.apple.imservice.iMessages.plist

Drag these two to the Trash and then restart the Messages app.

8:28 pm Tuesday; December 8, 2015

FaceTime, Game Center, Messages: Troubleshooting sign in issues

Messages – Can’t log in

Hi,

As Eric suggests resetting the App might be the way forward.

Are you still using Mavericks and Messages 7.x.x ?

Try the green marked Post in this Thread by Linc Davis

https://discussions.apple.com/thread/5275515

The Repair Permission item in the Disk Utility does not change the Home Folder Permissions but the instructions Linc has posted will do this.

It is possible you have lost Read and Write permissions to some of the .plists involved.

This will take a little while but is still quicker that checking about 20 .plists and the containing folders by hand.

AS he posts if you don't like the idea of using Terminal there is a Non Terminal way of doing the same thing.

10:07 pm Wednesday; December 9, 2015

Hi,

The App can only be reinstalled by Reinstalling the OS as it is effectively part of the package.

So...

This is Mavericks and the two .plists with iMessages in the name were in the ~/Library/Preferences folder ?

You have deleted these ?

You delete the two that Eric suggested ?

And you followed Linc's Green Reply in the other Thread that resets the Permissions and Ownership to you ?

In System Preferences > Date and Time the Correct Time Zone is selected (in the Map by City/town) ?

It is using the Automatic Server option to keep the time correct ?

In the Contacts App > Card Menu > My Card - this shows your details ?

In System Preferences > Region and Language you have a Regions set ?

9:04 pm Wednesday; December 16, 2015

Hi,

If you have done all of this and had no success it is likely that your Apple ID for the Mac use only has been blocked at the iMessages Servers.

Each device using iMessages has a unique login to the servers which involves the Serial Number of the device.

On the Mac it creates the IDS: Apple ID-Auth Token seen in the Keychain (The Italic bit is the email ID you use).

It seems that on Macs only that a security feature that uses this check is triggered and the Mac is then blocked.

The only solution is to phone Apple Support and have it reset.

Currently this is where the issue is.

When the Serial Number was first used a Pop up was seen if it was missing (OS X 10.8.2 and Messages 7.0.1)

There have been some related issue that have been solved the same way but it also seems people upgrading to El Capitan are also seeing this.

Level One people at Apple Support are Script led looking to solve Apple Care Hardware and Software issues.

Apple ID issues (which this is) are free to fix. They may try to charge you for the phone call.

Ask to speak to a Level 2.

Even then they are likely to want you to test in various different ways.
Some people reporting back have been told to Reinstall (not needed).

Insist that they reset the Apple ID on the iMessages servers for the Mac's use.

They may involve the Engineers who still seem to be looking for the trigger.

They may tell you that it will take 24 hours to reset (normally an overnight wait).

We haven't found a set of words that make this go any faster.

9:16 pm Thursday; December 17, 2015

Understood.

8:49 pm Saturday; December 19, 2015

Good to hear

7:46 pm Friday; February 26, 2016