Back in February, Apple's Worldwide Developer Certificate, designed to verify third-party apps and services, expired, requiring Apple to issue a new certificate for developers to use.

As pointed out by TidBITS (via Ars Technica) a side effect of the replacement of the certificate causes older OS X installers to fail to launch. OS X installation files downloaded from the Mac App Store before February 14, 2016 and stored on a computer or USB drive are no longer functional. This includes installation files for OS X El Capitan and older versions of OS X like Mavericks and Mountain Lion.

oldosxinstaller

Image via TidBITS

Users who keep OS X installers on hand or have created USB install disks in case of emergencies should replace their files with new versions by re-downloading them through the Mac App Store using purchased history. TidBITS points out that some older versions of OS X, like Lion, will not be downloadable on newer machines. Users who can't replace an expired certificate can still use older installers by changing the dates on their machines.

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:

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. Once you have completed the installation, visit System Preferences > Date & Time to reset the system date.

Apple's certificate renewal process resulted in some problems for developers and Mac users back in November, as it caused multiple Mac App Store apps to display a "damaged" error and fail to open. Apple quickly addressed the issue and has helped developers transition to the new certificate.

Top Rated Comments

garirry Avatar
65 months ago
Apple needs to make it so that anyone can download any version of OS X at any time, even if it's not compatible with their system. It's annoying how I can't download any version of OS X on my MacBook because it isn't compatible, so I have to go search for another Mac and download from there.
Score: 22 Votes (Like | Disagree)
emm386 Avatar
65 months ago
Apple screwed up big time here, I'm sure we all remember. Essentially though, the certification system is what's broken here.
really annoying though I find is, that the plain simple user is no more the authority over his own system.

A user should always be able to override what a system thinks is its best intent. Even if it's the wrong decision, even if I have to deal with catastrophic consequences: I (and no one else) should be able to decide, what's happening on my system. I can live with my computer misbehaving and me having to carry the consequences. but I can not live with the fact, that I no longer am in control. Admittedly, not even Microsoft gets this nowadays. at least not to the level I used to.
Score: 13 Votes (Like | Disagree)
pat500000 Avatar
65 months ago
This is stupid. I don't believe people as the consumers need to deal with this issue. This should have been resolved long time ago.
Score: 11 Votes (Like | Disagree)
0815 Avatar
65 months ago
But be careful not to set the date to January 1st, 1970 ... you don't want to brick your mac ;)
Score: 10 Votes (Like | Disagree)
firewood Avatar
65 months ago
You simply re-download a new copy? Sounds like a non-issue.
Unless you are located somewhere remote with no broadband or even any reliable internet.
Score: 9 Votes (Like | Disagree)
N10248 Avatar
65 months ago
Yay more downloading for me...

Score: 7 Votes (Like | Disagree)

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