Q: Cant sign in to messages

Hi,

There can be several causes and reasons for this.

NVRAM (PRAM) resets are a good start.

Safe Boot is also good.

Can you go to the Apple Icon Menu top left and use the About this Mac option.

In the Overview tab the Serial Number should be seen.

This is used in a Device Specific Login to the iMessages server (along with the Apple ID and Password)

Is it showing ?

If it is go to Applications/Utilities and open Keychain Access.

Select "Login" top left if it is not already.

Select "Passwords" Lower left.

On the right hand side look for

IDS: YourAppleID-Auth Token

The "YourAppleID" should be the emails used as your Apple ID in iMessages.

Delete this item but leave Keychain Access open.

Restart Messages and try to login again.

Is the IDS item recreated ?

If not then open a Finder window and use the Go Menu whilst Holding down the ALT key.

Select the Library and then navigate to Preferences.

Find these two items:-

com.apple.imessage.bag.plist  Holds the last server iMessages was connected to.

com.apple.ids.service.com.apple.madrid.plist  Holds the Apple ID and any alternatives listed in the app.

Restart Messages (both will be recreated if it works).

Does it work ?

This is about as much as you can test/do with your own Mac User account and the one Apple ID

If you have access to another Apple ID try that.

Does that work ?

In System Preferences > User and Groups you could Enable the Guest account or specifically create an Mac User account for testing.

Login to that Account

Set up iMessages with your normal Apple ID

Does iMessages account Login properly ?

If it does we will have to look deeper at  your normal Mac User account.

If it does not it is likely that the Apple ID has become blocked at the iMessages server level (it's a security feature that is supposed to stop people pretending to be you - based on the Device Specific login - but for some it gets triggered when it should not be but there is no reset on the Mac end.

Post back at this point as the details for the "Fix" are log winded and this posy is long enough already.

9:42 pm      Thursday; September 1, 2016

Has the Apple Support considered that there is an issue with the Apple ID? If the suggested steps by Ralph did not work, maybe you try to change your Apple ID password to make sure there is not something like a database hickup.

Hi,

I would not change the password if the Apple ID is working in iTunes, Photos, Mail and other linked Apple sites.

It would tend to highlight that the issue is with the iMessages server.

9:49 pm      Thursday; September 1, 2016

This is why I stated to do this if nothing else works. Changing the passwort of the Apple ID causes several processes on Apple's side (I don't know the details), which can sometimes fix those "strange" issues

Hi,

Just to say it is late where I am and I will be back in about 20 hours (Sleep, work, eat)

9:58 pm      Thursday; September 1, 2016

Jimmer Fredette wrote:

 

I tried to reinstall OS x - it wouldn't even let me!

What do you mean by that? Was there an error or something?

Jimmer Fredette wrote:

 

I guess this is because when I do finder -> go with ALT -> there is no two items such as

com.apple.imessage.bag.plist  Holds the last server iMessages was connected to.

com.apple.ids.service.com.apple.madrid.plist  Holds the Apple ID and any alternatives listed in the app.

So you checked the folder /Users/<yourusername/Library/Preferences, right? Have you check the log files using /Applications/Utilities/Console.app? Just open it and search all log files for "messages" or other related keywords.

Hi,

If the app has never managed to login then those .plist will not have been created.

I was under the impression this computer had logged in but now didn't.

A poster called polarbreeze has posted in this thread Re: Can't login to iMessage and FaceTime

It appears that Apple may have found the issue.

In most cases the Ethernet card/port gets numbered en0 and then Wifi Card is en1 with other options you may have getting subsequent numbers (Thunderbolt en2 and Blue Tooth en4)

You can check in both System Info and the Network Utility.

The fix is to remove the System side .plist for this  and reboot the computer.

7:46 pm      Tuesday; September 6, 2016

Messages – Can’t log in

Messages - Error Processing Registration