mac app store error 103 - trying to update and get this.

have you tried any of the suggested steps to attempt to fix the issue?

I had this problem immediately after upgrading from Snow Leopard to Mountain Lion. I fixed it as follows. I'm not sure if all steps are necessary, but the sum of all of them fixed my problem.

1. Quit App Store (if running)
2. Start iTunes
3. From "Store" menu, select "Authorize This Computer". I was prompted for my login credentials, then got a message that the computer was already authorized.
4. Start App Store
5. From "Store" menu, select "View My Account". I was prompted for my login credentials, then my account details were displayed.
6. Go to "Updates" tab on App Store. This time the update worked with no errors.

Hope that helps...

Thanks

Thanks @Dave Lasker, it worked! (y)

😀

Thank you very much.

I tryed this, but the same error is back again!

unfortunately.. me too

Me too, I did exactly what Dave Lasker said to do, but i still get the error 103

For those still going crazy with this (it happened to me for iTunes update 11.0.2) it's possibly a sign that the App Store's update-related files are dain-bramaged and it is too (ahem) unsophisticated to figure out how. In my case there were multiple files potentially related to the iTunes update and it wasn't able to resolve the issue (say, by re-downloading the file/files.)

Looking in the file /var/log/install.log I saw lines that looked like this:

Feb 26 10:55:59 XXX.local Software Update[734]: Local product zzzz041-9792 has two packages for identifier com.apple.pkg.iTunesXPatch: will use iTunesXDelta.pkg instead of iTunesXPatch.pkg

Feb 26 10:55:59 --- last message repeated 5 times ---

Feb 26 10:55:59 XXX.local Software Update[734]: SoftwareUpdate: Invalid or incomplete local product zzzz041-9792

Feb 26 10:55:59 XXX.local Software Update[734]: SUAppStoreUpdateController: error installing product zzzz041-9792: An unexpected error occurred.

The problem files are located in /Library/Updates/<uniquename>/ where <uniquename> will be the name folowing the word "product" in the log lines above (in my case, zzzz041-9792). The offending files appeared to be "iTunesXDelta.pkg" and "iTunesXPatch.pkg".

To solve the problem I simply moved those files out of the way, restarted the App Store and clicked the update button. For example, from the Terminal command line:

# sudo mv /Library/Updates/zzzz041-9792/iTunesX*.pkg /tmp/

(You could alternatively just delete the files; I was being paranoid. You could also use the Finder to move/delete the files, if you prefer.)

Hope that saves somebody the hour of frustration I just donated ...

Thanks, wojowoof. Your solution did the trick for me when the basic steps didn't.

wojowoof, THANK YOU for the heads up on the 2 files which were causing issues. I ran through all of the auhtorize/de-authorize and quit, re-open steps to no avail.

Going into Finder and selecting to "Go," selecting "Go to folder" then entering "/Library/Updates/" gave me access to the 2 files you mentioned in your post. I copied them to my desktop, then deleted them from the folder. Bodda-bing, my update was applied. After that I deleted the files on my desktop, and my folder now only contains a couple of .plist files (PPDVersions.plist and ProductMetadata.plist).

iTunes is working properly and the App Store is working as well.

Thank you again!

When I look in the/Library/Updates/ thera are only the PPDVersions.plist and ProductMetadata.plist-file, is this meaning that my computer has solved the problem it self (I didn´t do anything anyway)?

I can´t check because there are no updates to do now.

Great, this worked for me as well!

Thanks for all all the suggestions, especially wojowoof and aknotious for the offending files and the easiest way to deal with them.

You're the man. Thanks.