This copy of the Install OS X El Capitan application can't be verified

How to fix:

This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading.

It's not often I'll rebuild one of my Mac machines from scratch. Why would you? Anyways, now and again I do. Ran into an interesting error the other day - this one:


After looking, the USB stick I'd created for installing the unit came from an older version of the OSX El Capitan installer, dated back in November 2015. I suspect the certificate signing had expired or something like that. Anyways, easy to fix.

When you've booted from your USB installer, go to the utilities menu and run Terminal. In Terminal, we're going to set the date to a date shortly after the download date of the installer.


For mine, I could see I'd downloaded it circa 12 November 2015. So I'm going to set the date to November 30 2015. From Terminal, enter this command:

Date 1130170015

Bit of an odd layout isn't it? The format of the command is actually:

Date (Month)(day)(hour)(minute)(year)

…each with two digits. So I've set mine to 30 November, 17:00, 2015.

If you want to check the date was properly set, just type date without any parameters. Once you've done that, exit terminal, and install OSX.

Anyways, set the date, and re-run the installer. It should run just fine. You can then update the machine appropriately…and download a later installer at your leisure.

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