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   Previously Downloaded OS X Installers No Longer Work

   Josh Centers

   File this one under 'Obscure problems that could ruin your day.'
   TidBITS reader Randy Singer reports that due to an expired certificate,
   OS X installers downloaded prior to 14 February 2016 won't work.

   [1][tn_Obsolete-installer.jpg]

   The [2]Apple Worldwide Developer Relations Intermediate Certificate is
   required for all apps in the Mac App Store, including OS X installers
   When used to sign an app, the certificate enables OS X to confirm that
   the app has not been corrupted or modified by an attacker. This
   certificate expired on 14 February 2016, causing error dialogs and
   preventing some apps from launching. Most apps affected have already
   been updated with the new certificate. But if you downloaded an OS X
   installer in case of trouble, you may be in for a surprise the next
   time you try to use it.

   Happily, this is an easy problem to fix ahead of time:
    1. Delete any old OS X installers in the Applications folder or in
       other locations. They have names like Install OS X El Capitan and
       Install OS X Yosemite.
    2. Open the App Store app by choosing Apple menu > App Store.
    3. Click the Purchased tab. Enter your App Store password if prompted.
    4. Scroll down to the OS X installer you want and click Download.
       [3]Image

   The new installers are signed with a certificate that expires on 7
   February 2023, so it will be quite a few years before Mac users are
   affected again.

   Those who have created any bootable install disks for OS X will need to
   recreate them with the new installers. Dan Frakes wrote a [4]guide to
   creating OS X 10.11 El Capitan install disks for Macworld.

   If you begin an OS X install and get tripped up by the expired
   certificate, Randy Singer offers a suggestion on how you can work
   around the problem temporarily:
    1. In the OS X Installer, choose Utilities > Terminal.
    2. Enter date 0201010116 and press Return.
    3. Quit Terminal and continue the install.

   That Terminal command sets your system date to 1 February 2016 ' before
   the certificate's expiration ' so the installer can continue. Thanks to
   Randy for the heads-up on this issue and the workaround!

   As noted, this expired certificate affects more than just OS X
   installers ' [5]a number of Mac App Store apps suffered from it as
   well. If downloading a new version of an affected installer isn't an
   option for some reason, [6]Rich Trouton noted in 2012 that there's an
   -allowUntrusted flag for the command line installer utility that might
   help, as might [7]Greg Neagle's flatpkgfixer.py tool.

   As indicated by those posts from 2012, this is only the latest in a
   series of expired certificate snafus that have rendered Mac App Store
   apps unusable ' the last one hit in November 2015 (see '[8]The Mac App
   Store Is Breaking Apps,' 12 November 2015). Put bluntly, Apple needs to
   do a better job in managing its Worldwide Developer Relations
   Intermediate Certificate and alerting both users and developers to the
   implications of any expiration or revocation. Having this sort of
   sporadic failure is decidedly a strike against 'It just works.'

References

   1. http://tidbits.com/resources/2016-03/Obsolete-installer.png
   2. https://developer.apple.com/support/certificates/expiration/
   3. http://tidbits.com/resources/2016-03/App-Store-Download-OS-X.png
   4. http://www.macworld.com/article/2981585/operating-systems/how-to-make-a-bootable-os-x-10-11-el-capitan-installer-drive.html
   5. http://mjtsai.com/blog/2016/02/16/more-mac-app-store-certificate-problems/
   6. https://derflounder.wordpress.com/2012/05/17/10-7-4-command-line-installer-tool-can-now-install-installer-packages-with-expired-certificates/
   7. https://managingosx.wordpress.com/2012/03/24/fixing-packages-with-expired-signatures/
   8. http://tidbits.com/article/16081

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