Requiring the authorization of kernel extensions (kexts) is a new security feature as of macOS 10.13. Symantec Endpoint Protection 14.0.1 adds support for macOS 10.13. You must authorize the kernel extension for Symantec Endpoint Protection to fully function.
During installation of the client, click Allow when you are prompted under System Preferences in the Security & Privacy system preference pane. You do not need to enter a password.
The option to allow the Symantec Endpoint Protection kernel extensions in the System Preferences disappears after 30 minutes. You can get the option back in the following ways:
Restart the Mac. You can then open the Security & Privacy system preference.
Open the Symantec Endpoint Protection client user interface on the Mac and click Fix next to the message Kernel extensions need authorization. This action opens the Security & Privacy system preference.
If you have previously authorized the Symantec Endpoint Protection kernel extension on the Mac computer, you do not need to authorize it again. For example, you do not have to authorize the kernel extension again if you uninstall and then reinstall the client. You also do not have to explicitly authorize if you upgrade Symantec Endpoint Protection to 14.0.1 and then upgrade the operating system to macOS 10.13.
However, you need to reauthorize the kernel extension if you reinstall the operating system. You must also reauthorize the kernel extension if you upgrade from a Symantec Endpoint Protection version earlier than 14.2 to version 14.2 or later.