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Can't verify El Capitian download and will not start installation

I downloaded the OS and ran the script in terminal to install it on the usb stick. After starting the Mac and following the instructions I get the error message that the copy of El Capitan can't be verified. What went wrong? I am installing to a new formatted hard drive.


Thanks in advance!

MacBook

Posted on Jan 22, 2021 7:54 PM

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Question marked as Best reply

Posted on Jan 25, 2021 7:20 AM

I had the same issue.


I don't know the root cause but my guess was a certificate expiry error. I did this and it worked:


boot in recovery with your USB install media

disable WIFI (yes, WIFI was still on with booting from usb stick!!)

open terminal

change the date:

November 16th 2018 21:16 would become the following command:

date 1116211618

verify with the date is correctly updated:

date

(it should show the date in 2018)

exit terminal

install OS


(note: installing OS is only overwriting your existing MACOS

if you want a clean/fresh install, you first have to erase you SSD disk with disk utility and create a new partition (keep the same parameters as your existing partition)

2 replies
Question marked as Best reply

Jan 25, 2021 7:20 AM in response to wvictor21

I had the same issue.


I don't know the root cause but my guess was a certificate expiry error. I did this and it worked:


boot in recovery with your USB install media

disable WIFI (yes, WIFI was still on with booting from usb stick!!)

open terminal

change the date:

November 16th 2018 21:16 would become the following command:

date 1116211618

verify with the date is correctly updated:

date

(it should show the date in 2018)

exit terminal

install OS


(note: installing OS is only overwriting your existing MACOS

if you want a clean/fresh install, you first have to erase you SSD disk with disk utility and create a new partition (keep the same parameters as your existing partition)

Jan 22, 2021 10:38 PM in response to wvictor21

Where did you get this copy of El Capitan. If it can't be verified it may be the download got damaged while downloading.

Delete it and try downloading again. Use a cabled connection to your router, do not use the mac while it is downloading

or any other devices that share the same internet connection.


This is how to download El Capitan. click on the link below.


How to get old versions of macOS – Apple Support


Go to Download OS and click on OS X El Capitan 10.11

this downloads InstallMacOSX.dmg to your Downloads folder.


The next section can only be done on a mac that is capable of running El Capitan,

a mac that came preinstalled with an OS later than El Capitan will refuse to do the next bit.


When downloaded open to InstallMacOSX.pkg, double-click on

that and an installation window will open, this does not install El Capitan

but converts the InstallMacOSX.pkg to the Install OS X El Capitan.app which 

you will find in your Applications folder, it should be 6.2GBs in size.


(If the installation window asks which disk you want to install to, you must pick 

the disk that you are booted to at the time. Not any internal or external disk that 

you want to eventually install El Capitan on, that is for later.)


Create a bootable USB installer disk using the Install OS X El Capitan.app in the Applications 

folder and the createinstallmedia command in the Terminal app. 


Read the instructions here,

How to create a bootable installer for macOS – Apple Support


How did you format the new drive.

From the bootable USB installer you would open Disk Utility.

Highlight the Disk not any indented Volumes and click Erase.

Give the Disk a name.

Format: Mac OS Extended (Journaled).

Scheme: GUID Partition Map.

Click Erase.

When Done quit Disk Utility.

Select Install OS X.

The installation procedure should start follow the prompts.

Can't verify El Capitian download and will not start installation

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