Not Found! – update-core.php, themes.php, plugins.php, options-general.php

I have a local development environment and am no longer able to access update-core.php, themes.php, plugins.php, and any of the files under settings (options-xxxxxx.php). The only message I get is the “Not Found” My local server is running PHP 5.6.10.

I have tried https://wordpress.org/support/topic/not-found-update-corephp-themesphp-and-pluginsphp?replies=3 and all it does when I try to add the line to the .htaccess file is download a copy of the html file.