How can I resolve a .htaccess internal server error setting up a WordPress multisite?

You may need to set “AllowOverride All” in your apache config, for the Directory block for the server root, or root of your WordPress install.

Here’s what the relevant block looks like on a *nix system; things will probably look a little different on Windows:

<Directory /var/www/>
    Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order allow,deny
allow from all
</Directory>

The AllowOverride tells Apache that .htaccess files are okay; without it, it will ignore the contents of any .htaccess files it finds.

hth,

~ Patch