If you have trouble to make permalink works on your localhost’s WordPress you can use these steps to make it works. But, you have to make sure that you are using Windows and Apache2.2 as your local server.
When you point your browser to the address of your page or post that has custom permalink in it, say http://www.test.com/about/, it shows page Not Found “The requested URL /about/ was not found on this server” like this one. You may try the solution as follow.
Continue reading Enabling WordPress Localhost Permalink to Prevent 404 Not Found
You should know that localhost can be accessed trough
Depending your default configuration on your Mac. In Mac you can access your localhost by http://localhost/username/. If you have trouble with http://localhost/username/folder/ shows 404. It is maybe about permalink and .htaccess on your webserver.
In this case, WordPress won’t show up. So, the problem can be your webserver settings.
Please learn about MacOs localhost trouble.