If your computer is managed by Jamf (usually if it’s used in a corporate environment), an incorrect System Policy configuration can cause the installation of the Little Snitch network extension to fail with the following error message: “The system policy prohibits activating the system extension.”
If you are encountering this problem please contact your system administrator and ask them to verify the configuration entry of the Little Snitch network extension:
Team Identifier: MLZF7K7B5R
Allowed System Extensions: at.obdev.littlesnitch.networkextension
If you also want to install the Little Snitch Endpoint Security system extension, make sure to add at.obdev.littlesnitch.endpointsecurity to the list of allowed extensions.