Update Wordpress failed to update to version 4.1.1

An error occurred when I tried to update Wordpress to 4.1.1

Update WordPress
Downloading update from https://downloads.wordpress.org/release/en_AU/wordpress-4.1.1.zip…

Unpacking the update…

Could not copy file.: wordpress/wp-content/themes/twentythirteen/style.css

Installation Failed

Can you please tell me what we need to do in order to fix this so that it doesn't happen again?