So perhaps you’re getting these errors?
iCloud
Unable to sign in because of a problem communicating with iCloud.
Try signing again.
App Store
An unknown error has occurred.
FaceTime
The server encountered an error processing registration. Please try again later.
Messages
The server encountered an error processing registration. Please try again later.
Perhaps you may say, “Gasp! This is supposed to be a hackintosh issue, and not an issue on genuine Macs!”
Fear not, my friend, if you have committed the ‘grievous sin’ of moving your Mac’s hard disk into another Mac. (As a penance, say 10 hailmarys quickly.) For you see, on occasion, Mac may get confused about your networking devices when you do this.
What do networking devices have to do with all this? If you read hackintosh forums, you’ll see that Apple seems to use your primary ethernet network card’s MAC address to identify the machine. And communicates the identity in some shape or form when you log into the aforementioned services.
Problem arises when your Mac’s primary ethernet card cannot be identified.
Cure for your transgression? Aside from those hailmaries, you’ll also want to delete (or move aside, or rename) /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist. Then reboot. Behold! This file should be magically regenerated, and your access to iCloud and Mac App Store should be restored.
You’re welcome.
Naturally I’m not responsible if deleting this file harms your Mac, or if you do it yourself in process of deleting this file. Have an expert around. Then again, if you did move the disk around, you probably are the expert.
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via blog.vucica.net
After having my hard drive replaced and then restoring via Time Machine, I ran into a communication error with iCloud, just as you described. Your solution worked like a charm. Thank you!
Hey, I just repaired my macbook air 2,1 (late 2008 model) at the Apple Store and got a new hard drive installed. The thing is, I am also having the "unknown error" problem when trying to log in to the App Store. Unfortunately, I do not see the SystemConfiguration folder in the Preferences folder. Please help me! Thanks in advance!
If you are looking in the system-wide user-configurable Library folder — that is, the /Library folder, and not the /Users/username/Library nor the /System/Library folder — it should be there. If it is not, I suspect some overzealous maintenance program deleted it. I don't think Apple's servicing personell or a program that their personell uses it would delete it, but if it's missing — well, from what's stored in that folder, it doesn't sound right.
You could try just creating this folder and seeing if you get out of this mess. If not, a reinstall is in order. So, first try creating /Library/Preferences/SystemConfiguration, reboot, and see if it's filled with files, and if App Store now works. If not, get someone to back up your home folder, reinstall, and (if needed) put the home folder back in place.
I saw this info on other sites and tried it (along with a bout 6 other suggestions).
No go I'm afraid.
I'm at my wits end
I had the same problem and nearly reinstalled OS X because of it, but I found a solution: just install the latest OS X combo update (in my case, the 10.8.2 combo update).
You saved me man.
Thanks a lot. Last time when it happend I was not able to solve it.
Your advice worked like a charm!
Thanks!
Thank you SO much! been looking for this solution for 2 years. Decided to try again today and found this. THANK YOU!
I reinstalled maveriks and it didn't work, but deleting the plist file worked like a charm for me. Thanks!!