In the past couple of days, many client sites have gotten notices from Google Webmaster Tools about being unable to access CSS and JS files.
The most widespread issue was blocking of wp-content, wp-includes and wp-admin in the robots.txt file. Googlebot is now smart enough to not crawl these items by default, so they can be removed.
The second issue we found was related to the Wordfence plugin. As of version 6.0.12 Wordfence includes a call to a dynamic script located in wp-admin, which is a default “Disallow” entry in the WordPress robots.txt file. Upgrading to Wordfence 6.0.14 or later will fix this issue.
Users of WPCmdCtrl are already covered and have the update 🙂