Upgrading to El Capitan with an old installer

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I upgrade my Macbook to El Capitan as soon as I could, and have had very few
issues with the release. On my iMac at work though, I’ve been putting off the
upgrade since last October – due to time constraints and not wanting to mess
anything in my dev environment up.

Today I tried to install El Capitan using the Install OS X El Capitan.app
installer.

[IMAGE: https://blog.omgmog.net/images/2016-08-03/installer.png]

I was greeted with this message. How could this be? The installer has simply
been sat in my Applications directory since October, nothing has changed.

I used the following command to verify the integrity of the installer image:

hdiutil verify /Applications/Install\ OS\ X\ El\
Capitan.app/Contents/SharedSupport/InstallESD.dmg

Which told me the image is VALID. Alright, so there must be another cause?

Well I downloaded the installer in October 2015; In February 2016 Apple’s
Signing Certificate expired. I actually encountered this issue when doing a
fresh install of El Capitan on another Macbook earlier this year, the solution
is simple: change the system date to earlier than February 2016.

date 1021120015

That command changes the date to October 21st 2015 at 12:00.

Alternatively you can use the Date & Time System Preferences pane:

[IMAGE: https://blog.omgmog.net/images/2016-08-03/datetime.png]

Now you can run the installer without issue.

After OS X El Capitan has installed, it will set the date and time back to their
correct values.

Now, rather than having to re-download a 7GB installer image, I just have to
download a 2GB update!

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Published August 03, 2016

Generated from the original post:
https://blog.omgmog.net/post/upgrading-to-el-capitan-with-an-old-installer/


Max Glenister is an interface designer and senior full-stack developer from
Oxfordshire. He writes mostly about front-end development and technology.

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