Mac Pro - Yosemite - iMessage won't connect

Just reset PRAM worked for me (thanks steveyears)

Didn't have to do Safe Mode step.

My problem was Message login would hang, couldn't log in (all other apps worked)

Tested that I could log in under guest user account, yes.

Mac Pro mid 2010, Yosemite 10.10

2009 Mac Pro + yosemite

1) Reset your computer's PRAM

2) Boot your computer in Safe Mode

3) At this point I was able to log into FaceTime and Messages

4) Reboot into Normal Mode

did not solve it for me
imessage doesn't work and Yosemite has definitively a ton of bugs

Hello, it doesn't solve my problem.

Is there another ways?

I have had a lot of problems regarding my keychains after installing the final version of Yosemite on my MacPro 2008. I had to run some script that corrected all of my rights (running disk utility did not fix it) and after that I could actually use my personal account again. All other accounts on the computer has worked OK. Now I noticed that FaceTime and iMessage did not connect but my password worked OK to login from other computers and onto iCloud.com so I did know that is was no error there. I tried the PRAM reset and then I was able to login to FaceTime and iMessage again but I can't send any messages with either program. My share button in Safari says only "no service" when I try to share a link or something.

What is this ?!?!? Please make a fix for this problem promptly c'se I and a lot of others has a lot of problems with this. Do I have to reinstall the computer just to get one out of four accounts to work (where the other three works perfectly fine) ?

I Also updated to Yoshmite. Had problems with slow starting chatted to Apple help and remove a lot of stuff. It seemed to work ok. Then today it turned itself of or went to sleep. It is fully powered. No matter what I try it won't turn on. I took it to the genus bar at the Apple Store. They would not look at it said I had to book an appointment. Now I have to wait another week. Not a good response from Apple

I got the solution.

I tried all the above and that didn't work.

However, what I did was

1. Goto system preferences

2. Select Internet Accounts

3. Click on iCloud on the left pane

4. entered my credentials

5. Saved and tried iMessage and it works now.

Right now iMessage and FaceTime do log on, but I can't send any messages / start FaceTime calls... iMessage, for example, just says "not delivered" (translated from swedish to english).

What's causing this ?

I also tried the PRAM – Safe Boot method and it didn't work for me either.

So I thought, maybe it was an network issue? So I logged into the Guest account, fired up Messages and I was able to log in just fine....!!

Cool, so network is fine (read: IT isn't blocking anything). So I logged out of the Guest account, logged back into my account, fired up Messages and ta-da! Messages logged in just fine.

Everything is working as should for me now. Maybe try your guest account with Messages?

Good luck.

I activated my guest account but I was not able to run a single program there, none, just like I was unable to do in my own profile like I wrote earlier.

I'm getting "a litte tired" on this right now since the other accounts did not have any problem at all after the upgrade to the final version after that I had run the public betas on it, without any problems like this.

What can be causing this? Is anyone at Apple reading this forums?, if so please help!

Excellent, I've been having the problem since Mavericks on my Late 2008 MBP. Just tried it and it works fine now!

... Oh, and as a welcome side-effect, it also solve a problem that just started occuring a week ago. Neither iPhoto nor Aperture were syncing from iCloud Photos or Photostream, even though it was activated in the System Preferences.

Anyone know how to reset the parameter RAM on my headless Mac Mini? I guess I'll have to connect a wired keyboard, eh?

Here's what I did!
"Turned on WiFi and updated "Set time zone automatically" (Should be in general settings!)

- Found from this post: Could not sign in to iMessage.

Same problem with no solution. Tried everything including new OS instal. Does not work on Mac Pro Early 2009 and does work on MacBook Pro.

I'm having the same issue on my late-2007 MacBook Pro, but not on my mid-2010 Mac mini server.

On the MBP, i've tried wiping the PRAM, resetting the System Management Controller, booting in safe mode, logging in as a guest... nothing works. There has got to be a corrupt preferences file or something that's causing this.

FWIW, this solved the issue for me as well.