Uploading an .htaccess file results in a 500 Internal Server Error.
If after uploading a .htaccess file the web site displays a 500 Internal Server Error then there is something in the .htaccess that is invalid or is using an option that is disallowed.
The most common cause of this error is use of the All or SymLinksIfOwnerMatch "Option".
The code in the .htaccess file will look similar to:
Option SymLinksIfOwnerMatch or
Neither of these settings are permitted. It will not alter the functionality of the web site by these settings being disallowed since the SymLinksIfOwnerMatch option is enabled globally and is simply being disallowed from being disabled. Without this setting FollowSymLinks is insecure and could permit the reading of site files owned by another user.