An unknown error has occurred app store

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.

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 network interface problem is known older problem. This is something new and the problem is on Apple's end. IOW it's something they changed which caused this. So far, none of the solutions posted has worked for me.

jconstantine, if you're in Terminal, you'll need to `cd` into the directory, then run `sudo rm -f NetworkInterfaces.plist`. The `sudo` bit runs the command after it with heightened security privileges (that of an admin). If you're trying to delete the file via Finder, then I'd expect the password prompt to show up.

I have two Mac Book Pro, one 13" using at Work and another 15" using at home. Everything is fine with MBP at home. I can use Mac App Store without any problem. But at office I guess it happened in last two weeks, I had a problem to sign in Mac App Store. I can navigate and look all apps in the Featured, Top Charts and Categories. But when I want to see Purchases, asks me to sign in. I enter my Apple ID and password correctly but it says "An unkown error has occured" and can't sign into Mac App Store. I've attached snapshot for this here. I searched forums and discussions on WEB and did many things like deleting files, ByHost, Network Pref etc. Everything I have seen on the WEB useful. But unfortunately couldn't pass that. I have other Apple products and my Apple ID works well at them also at WEB.

Yesterday, this problematic MBP at work installed updates for iPhoto and OSX Mountain Lion but didn't let me sign in.

Does anybody has a solution for that which is not written at discussion or at SERPs?

Thanks for the useful help, will appreciate deeply.

Still no luck, with either deleting the NetworkInterfaces.plist nor changing the permissions on Library/Cookies (even with -R recursion). It does work if I log in from a newly-created Administrator account, so it seems to be a problem with my user account.

The other day I even tried deleting many other things from my Library — many caches & preferences (all stuff I know isn't irreplaceable). No luck anywhere.

Hopefully someone can come up with another solution. But thanks for the info, mohd hatta & unixy_goodness.

~peter in oakland

Thanks njbc! That did it for me! I had tried a lot other suggestions, including a modification to the plist, and I even think deleting it, but no one had mentioned deleting from the trash before restarting. Praise God!

Thanks to all for their contributions. Unfortunately even the 'create a dummy account' option isn't working for me!

Pure speculation but I have a suspicion this is indeed tied into the network plist for some kind of newly rolled out copyright protection scheme that relies on the built in en0 MAC Address. I had a similar issue with Silverlight on the Mac I have with this problem, which is somewhat unusual in that the built in en0 is burned out and can't be created. So anything that relies on en0 being there dies a painful death.

Here's what mystifies me, though: If the bug does lie in a system-wide issue like the device's en0 MAC address, then why would App Store sign-in for a given Apple ID fail for one user account on the device, yet work fine for another user account on the same device?

That's my situation, which makes me think that the issue must lie in settings (Preferences, etc.) for the user account that can't sign in. Although my attempts to follow every suggestion and delete all possible offenders from the account's Library (and network.plist, etc.) is having no success.

(To clarify the situation: My main user account on my iMac has no trouble using my Apple ID for iCloud and other purposes, but simply cannot sign in to the App Store with that Apple ID. Meanwhile, another user account on my iMac can use that same Apple ID for App Store login, with no problem.)

Thus, I'm still looking for a user-specific issue causing the problem. No luck so far... : (

Strange!

I have encountered this problem too. I have tried various suggestions I've found on the web. I have also made a system recovery - but nothing have worked. Still the same old message: "an unknown error has occurred", whenever I try to sign in on App Store.

I've contacted the App store support - the last thing I heard from them was that they were investigating the issue (this was about two weeks ago now).

I run OSX 10.8.2 on a Macbook Air 11" (bought in July 2012). I can still use App Store on my old Macbook (Snow Leopard). Itunes works fine - it's only App Store that I can't access.

Thanks for the suggestion, but after deleted NetworkInterfaces.plist, always the same problem.I'ts very space because on the MacBookPro I've exactly the same configuration (I've compared settings many times for be sure) and there is not a problem with the Mac App Store on the Mac Book Pro.

Hey, what's this? Suddenly, today, the App Store works perfectly for me. I didn't do anything new; I just tried to install an app update on a whim, and it worked. New download/installation works too.

Since I did nothing on this end, it suggests to me that Apple quietly fixed something on their end. Anyone else able to confirm a fix?

I am trying to download Mountain Lion again so that I can make a bootable USB stick. However, I get the following error (the image is rather small; it say 'An error has occurred' and the DOWNLOAD button is just a gray box without any letters in it) displayed in the App Store. I've tried deleting the Cache.db and cookie files for the App Store, logged out and logged back in, called a psychic hotline, put my MacBook Pro in the freezer for 17 minutes...to no avail.

I am getting this very same problem, can log in and out absolutely fine on my iPhone. But my ipad (same apple Id) has stopped logging in I just get the same message unknown error has occured App Store. I've reset ipad, wifi settings, cleared history, tried creating new account to check terms and conditions as recommended then sign in again but still no success. Please help?

I have tried everything in this forum and nothing has worked for me.

I'm still getting Calculating and after about an hour it will eventually error out.

I talked with app store support and all they could do is refund my money.

they offered no possible solution for this.

I'm on a macbook air (purchased 1.23.13), with a total of 93gb of free space.

The application I'm trying to get is Civilation V.

I have also used a complete different network to download this with no success.

I also have a rMBP (purchased in mid 2012) that will not redownload MAC OS X mountain lion.

The funny thing is I have downloaded and installed it on that machine before.

Any help would be great.

Or I will just wait for an update from an Apple engineer.

Thanks