You’ll find sometime that when you deploy WordPress in order for permalinks to work correctly you need a proper .htaccess file. This .htaccess also affects anything else you place within your web root when WordPress lives.
For instance if you need to password protect a directory within the your webroot where WordPress lives. You’ll find that when you do so, and try to visit that folder in a web browser that a 404 WordPress page will be displayed. To fix this, you simply need to add the following to your main .htaccess file that has your WordPress rules.
ErrorDocument 401 default
This should then allow you to use your password protected directories as you normally would if you didn’t have WordPress installed.
I didn’t really know what to put for the title of this post, but hopefully the content makes more sense and gets indexed properly and found by people looking for this specific information.
The problem is when you install WordPress and setup Permalinks which uses a .htaccess file for Apache. The .htaccess make cause problems with other applications or HTML files you have in sub-directories in your document root.
The fix? It’s simple, just view this blog post. It explains to fix the problem you simply place “ErrorDocument 401 default” at the top of your .htaccess file and everything is resolved. Your WordPress installation still generates 404 pages, but now sub-directories work correctly.