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   Solving the App Store's NSURLErrorDomain Error

   Adam C. Engst

   All I really wanted to do was check the size of the iTunes 10.7 update
   for the TidBITS Watchlist item that I was editing, but the App Store
   app wasn't cooperating. (For those who haven't run into this in OS X
   10.8 Mountain Lion yet, choosing Software Update from the Apple menu no
   longer runs a separate Software Update application; instead App Store
   launches and shows the Updates view.) Instead of giving me the iTunes
   update, or even a sensible error message, the App Store app displayed
   the thoroughly inscrutable message 'The operation couldn't be
   completed. (NSURLErrorDomain error -1100.)' As far as I can tell from
   [1]Apple's developer documentation, this basically means that some
   requested file doesn't exist.

   [2][tn_App-Store-error.jpg]

   After moaning about Apple's uncharacteristically poor error message on
   Twitter, I got a note from Dennis Wurster, a friend and Mac consultant
   in Rochester, NY, saying that he'd solved the problem by switching his
   DNS settings to use [3]Google's public DNS servers (8.8.8.8 and
   8.8.4.4). I've been using OpenDNS's servers (208.67.222.222 and
   208.67.220.220) for some time now with no problems (for a reason why,
   see '[4]OpenDNS Blocks Flashback and Other Threats,' 16 May 2012), but
   when I changed the order of my DNS servers in the Network preference
   pane (select your current network adapter, click Advanced, then click
   DNS) to put Google's public DNS servers at the top, the App Store app
   was able to find and download the update with no problem.

   [5][tn_DNS-server-view.jpg]

   Others have had success with this trick as well, and Kevin Bush
   reported back to me on Twitter that when he switched back to his
   previous DNS servers after the App Store app found the iTunes 10.7
   update, it could still see it (perhaps due to caching) but couldn't
   download it. Freaky!

   I truly don't understand at the moment how switching DNS servers could
   solve this problem, but for anyone troubled by the error, Google's DNS
   servers are worth a try.

References

   1. https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Miscellaneous/Foundation_Constants/Reference/reference.html
   2. http://tidbits.com/resources/2012-09/App-Store-error.png
   3. https://developers.google.com/speed/public-dns/
   4. http://tidbits.com/article/13006
   5. http://tidbits.com/resources/2012-09/DNS-server-view.png

.