File this one under “Obscure problems that could ruin your day.” TidBITS reader Randy Singer alerted us that due to an expired certificate, OS X installers downloaded prior to 14 February 2016 won’t work.
- Mar 12, 2020.
- Nov 01, 2013.
- Jul 31, 2020 Mac Pro introduced in 2013, plus mid-2010 or mid-2012 models with a recommended Metal-capable graphics card. To find your Mac model, memory, storage space, and macOS version, choose About This Mac from the Apple menu. If your Mac isn't compatible with macOS Mojave, the installer will let you know.
Oct 30, 2019.
Mac Os X Installer Apple Store
The 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 affected apps have already been updated with the new certificate. But if youdownloaded 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:
- Delete any old OS X installers in the Applications folder or in other locations (be sure to look on external hard drives too; if the App Store detects an old installer, it won’t let you get a new one). These installers have names like Install OS X El Capitan and Install OS X Yosemite.
- Open the App Store app by choosing Apple menu > App Store.
Click the Purchased tab. Enter your App Store password if prompted.
Scroll down to the OS X installer you want and click Download.
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 guide to creating OS X 10.11 El Capitan install disks for Macworld.
There is one qualification to all this. Apple won’t allow a newer Mac to download versions of OS X that aren’t compatible with that Mac, so on a 27-inch iMac with Retina display, for instance, the App Store app refuses to let you download Mac OS X 10.7 Lion.
If you are in the middle of 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 quickly, without having to download a new installer:
- In the OS X Installer, choose Utilities > Terminal.
sudo date 0201010116, press Return, and enter your password.
- 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. Once you have completed the installation, visit System Preferences > Date & Time to reset the system date. 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 — 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, Rich Trouton noted in 2012 that there’s an
-allowUntrusted flag for the command line
installer utility that might help, as might 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 “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.”
You can upgrade to OS Yosemite on any of the following Mac models. Your Mac also needs at least 2GB of memory and 8GB of available storage space.
MacBook introduced in 2009 or later, plus MacBook (13-inch, Aluminum, Late 2008)
MacBook Air introduced in late 2008 or later
MacBook Pro introduced in mid 2007 or later
Mac mini introduced in early 2009 or later
iMac introduced in mid 2007 or later
Mac Pro introduced in early 2008 or later
Xserve models introduced in early 2009
To find your Mac model, memory, storage space, and macOS version, choose About This Mac from the Apple menu . If your Mac isn't compatible with OS X Yosemite, the installer will let you know.
Make a backup
Before installing any upgrade, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.
It takes time to download and install OS X, so make sure that you have a reliable Internet connection. If you're using a Mac notebook computer, plug it into AC power.
Download OS X Yosemite
For the strongest security and latest features, find out whether you can upgrade to macOS Catalina, the latest version of macOS.
If you still need OS X Yosemite, use this link: Download OS X Yosemite. A file named InstallMacOSX.dmg will download to your Mac.
Install the macOS installer
Double-click the downloaded file to open a window showing its contents. Then double-click the file within, named InstallMacOSX.pkg.
Follow the onscreen instructions, which will guide you through the steps necessary to install.
After installation of the installer is complete, open the Applications folder on your Mac, then double-click the file named Install OS X Yosemite.
Click Continue and follow the onscreen instructions. You might find it easiest to begin installation in the evening so that it can complete overnight, if needed.
Allow installation to complete
Os X Installer Mac App Store Login
Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar, or show a blank screen several times as it installs both OS X and related updates to your Mac firmware.
Mac App Store Updates
- OS X Yosemite won't install on top of a later version of macOS, but you can erase your disk first or install on another disk.
- You can use macOS Recovery to reinstall macOS.