Recently some Mac users complained in some social platform as well as Apple’s technical support forum that when trying to launch the software or games downloaded from Mac App Store, they were informed that “XXX is damaged and can’t be opened”. And they are required to reboot their machines, or even to delete this application and then download it again from the App Store. So far the popular software involved in this issue include 1Password, Acorn, Byword, Call of Duty 2, DaisyDisk, Tweetbot, etc. Now Apple has publicly made an emailed apology to the Mac App Store developers and gave a further explanation about this issue.

Apple addressed that it had issued a new certificate in September in anticipation of the old certificate’s expiration, and the Mac App Store signing certificate was updated recently. The old certificate used the SHA-1 hashing algorithm, but the new one had been upgraded to support SHA-2. So this bug was related not just to an expired security certificate but also a transition to a new certificate with stronger encryption that not all developers were ready for. And that helps explain why the system could not validate the application packages using old versions of OpenSSL that don’t support SHA-2. As for the caching issue with Mac App Store, Apple suggested users to reboot and reauthenticate with the store to clear outdated information from their systems when the new certificate went into effect. Additionally, Apple also asked OS X developers to ensure their code adheres to the Receipt Validation Programming Guide and if necessary, to resubmit their app for an expedited review.

As some news reports comment, this incident goes to show that the Mac App Store is not exactly the focus for the company right now, as Mac App Store doesn’t receive nearly the kind of attention lavished on its iOS counterpart. Mac developers have been hindered by many limitations of the store for years. They don’t have access to statistics or latest tools like TestFlight, and many practices such as free trials and upgrade pricing are not allowed in Mac App Store. Maybe Apple should put more effort in improving Mac App Store for its long-term development.

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