Fix an error when installing a new copy OS X
Roman Loyola reveals what to do when you see: ‘this copy of the install OS X application cannot be verified’
The other day a coworker needed to borrow a Mac, so I grabbed an older MacBook Air from storage. I decided to wipe out the laptop’s flash storage and install a fresh version of OS X. I created a bootable USB flash drive installer, plugged it into the laptop, pressed the Option key as the machine booted, and then selected the USB drive as the boot disk.
I then ran Disk Utility to reformat the drive and ran the OS X installer. It looked like things were moving along, until an error message appeared. I therefore created another boot disk using a different storage drive, in case it was a hardware problem, though I got the same error. I figured that the laptop being in storage for a while could have something to do with it, and it did.
This should work with Mavericks and El Capitan. It also worked for me with the macOS Sierra Public Beta, which showed a different error message – ‘The installer payload failed signature check’ popped up near the end of the installation.
Fix the problem
The installer checks the date on the computer. If the date isn’t current, you get the error shown on
the previous page. The fix involves correcting the date on your Mac.
If you have an older OS on the Mac
If you have a complete OS on the Mac already, boot into it. Fix the date in the Date & Time system preference (Apple menu → System Preferences). Reboot using the USB boot disk, and you should be able to proceed with the installation.
If you don’t have an OS on the Mac
If you are in a situation like I was, and you don’t have a complete OS on your disk (you reformatted it), you’ll find that there’s no way to access the Date & Time system preference when you use an external USB boot installer drive. The Apple menu doesn’t give you access to System
Preferences. You have to use the Terminal to set the date and time.
If you use an external boot disk, your Mac starts up into OS X Disk Utilities. You can access the Terminal by clicking on the Utilities menu and selecting Terminal. Once the Terminal has launched, follow these steps:
At the prompt, type date to see the date that’s on the Mac. For example, here’s the date of the MacBook Air I worked on
If your Mac is connected to the Internet, you can tell your Mac to check online for the current date and time. You can do this by typing at the prompt ntpdate -u time. apple.com and then pressing Return
Your Mac should now have the current date and time. If you enter date again (as I did in the previous screenshot) the information that appears will be current. You can now run the OS installer.
If you don’t have an internet connection
You can still use Terminal to set the date. Go into the Terminal as described earlier, then follow these steps:
At the prompt, type date to see the date that’s on the Mac Figure out the numerical representation of the date and time. The pattern you need to follow:
Month: in two-digit format. For example, July is 07. Day: in two-digit format. For example, the 7th is 07. Time: in military format of hours and minutes. For example, 2pm is 14:00 Year: Last two digits.
In my example, the numerical representation is 0719140016. This stands for July (07) 19, (19), 2pm (1400), 2016 (16). At the prompt, type date [numerical], with [numerical] being the representation you figured out. In my example, I typed date 0719140016. Then press Return
The date should be set. You can check the date again by typing date at the prompt. You can now run the installer.
This is the error message I got while trying to install OS X from a USB installation disk
How to access the Terminal when you boot from an external boot drive installer