Method 1: Change Date and Time Through Terminal With the causes of the error message now out of the way, we can get into the different methods that you can implement to install OS X El Capitan successfully. As a result, you will have you redownload the installer to fix this issue. In case the download process was interrupted or interfered with, it may result in the said error message.

Corrupted Installer - Lastly, the reason why this error message may occur could be a corrupted installer as suggested by the error message itself.

This can be easily fixed by just changing the current date of your Mac device. As a result, the certificates are expired and you are shown the mentioned error message. This happens when you use the installer at quite a later date from the time when you actually downloaded it.

Expired Digital Certificate - The main reason why this error message appears is when the digital certificate associated with the installer expires.

However, before we get into that, let us go through the causes. The solution to this issue is pretty simple and can be easily implemented. Users have tried downloading the installer again but in most cases, it does not work out either. We will be discussing the causes in detail down below.

There is another major reason why this error message can occur and that is the digital signature that comes with the installer. While that can be the case in some scenarios, it does not always hold true.

This Copy of the Install OS X El Capitan Application Can’t be Verified Error Message The error message suggests that this copy of the installer may be corrupted due to which the issue is occurring. This error message occurs when your Mac device reboots in order to begin the installation phase. One of the errors that users face while upgrading to the OS X El Capitan is the “ This copy of the Install OS X El Capitan application can’t be verified“. However, when the installation does not go as planned, it can become tedious especially if you are aware of what the error message means. Installing a new version of the macOS operating system is always exciting and intriguing.

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