An unknown error has occurred app store

same problem on macbook air running 10.6.8 and wanting to download Mountain Lion.

I can't log in to App Store either. My TuneUp app keeps saying it was downloaded from another computer and needs me to sign in to download from the App Store. It was downloaded on this machine. It's the only one I have at the moment. I rebooted the machine, changed password twice, but nothing works. I keep getting "An unknown error has occurred" message. This has been happening for the past couple of days.

Same issue for me. Macbook Pro running 10.8.1. On my Mac Mini my login from App Store works, but not from my laptop.

Same here. In the last couple of days I have seen a lot of discussions in the community forum describing the problem. Neither solution I found worked for me.

I'm having the same issue on an iMac with 10.7.4. Mac Mini, iPad and iPhone all work fine with App Store. Spoke with tech support. They suggested reloading OS. I did, but only change was that Safari kept crashing. Reloaded Time Machine backup to get browser working again. Very frustrating!

I have the same problem. "An unknown error has occured" when trying to sign in App Store, or update softwares, or buying stuff. I am sure that it registers correct username and passowrd, for otherwise I would get "Your Apple ID or password was entered incorrectly." I have tried all suggestion, removing the whole appstore folder from the Library Cache, but it did not work.

My problem turned out to be network related. I added a wireless airport card to my Mac Pro and disabled the onboard ethernet that was named "en0" (computer not near to a port). This caused my wireless card to be renamed to "en0". Why is this a problem? Apparently, the system checks that the onboard ethernet is working properly before allowing acces to the App Store. If onboard ethernet is not working, it'll display that cryptic message. To fix this:

1. Click on Apple menu and choose "System Preferences..."
2. If the wireless (or some other piece of network hardware other than onboard is name "Ethernet (en0)", delete it.
3. Make sure the onboard gets renamed to "Ethernet (en0)". If it was somehow deleted, you'll have to recreate it by clicking on the "+" sign and choosing the onboard port. This has to be done even if the port isn't connected to anything.
4. The other port can be recreated afterwards

I know it's a pain.

My problem is clearly not network related. If I create another user and login as that user then use my account with App Store then I can successfully log in. Must be something in my own account.

I've tried all the other things like removing ~/Library/Caches/com.apple.appstore/Cache.db and ~/Library/Cookies/com.apple.appstore.plist. There must nbe another corrupted file somewhere in my account that is causing the problem.

My network interfaces are ok. I tried to track down the App Store login process and discovered, that the following error message is written into my /var/log/system.log

Sep 16 01:52:13 MacBookPro.local App Store[40652]: [IMKInputSession deactivate] exception caught.

IMKInputSession:<IMKInputSession: 0x7f83392c0870> --

NSInvalidSendPortException : [NSMachPort sendBeforeDate:] destination port invalid

The NSMachPort class is used for distributed object connections on the local machine. Seems the login process has problem with interprocess communication.

An update. I get the following errors logged in /var/log/system.log:

Sep 15 20:43:04 chappell com.apple.ShareKitHelper[439]: --warning: [ShareKit-XPC] Received XPC_ERROR_CONNECTION_INVALID

Sep 15 20:43:04 chappell com.apple.ShareKitHelper[439]: --warning: [ShareKit-XPC] connectionWithClientInterrupted

Sep 15 20:43:04 chappell com.apple.ShareKitHelper[439]: --warning: [ShareKit] Cancel UI for running services with Client PID: 961

Sep 15 20:43:04 chappell Dock[310]: LaunchPad: __53-[LPAppManager(StoreSupport) _acceptStoreConnection:]_block_invoke_0 app store xpc message error: Connection invalid

Any ideas?

The problem is definitely associated with my account. I created another account and I can connect AppStore and update my apps.

100% same problem and errors here: logging in to App Store also succesful from another user account, same tricks tried on Cache ans plists without any success.

Help, please!?

same problem here. I already explained the problem in another thread:

https://discussions.apple.com/thread/4259595

email discussion with apple support did not help...

hope the problem will be fixed automatically with 10.8.2. as a temporary and inconvenient solution one can use a second user account on the same mac to update or install apps.

I ended up re-creating a new user account and moved all my stuff across to this new account; everything back to normal.

But of course, we can hope someone somewhere will eventually come up with a more user-friendly workaround!

That is a workaround, not the solution. Looks like a solution from Windows world.