Since the upgrade client has had increasing problems with media. One day was unable to edit feature post thumbnails and save the settings. Next day all feature post images have vanished from theme display, both on the front-page.php where displayed and on the single.php where displayed. Featured images already set can be seen on the post panel in the admin, however new feature images cannot be set. Attempting to delete an image from a post deletes it from the admin panel, however the files are not deleted from the server.
Tried all here (http://wordpress.org/support/topic/troubleshooting-wordpress-35-master-list?replies=4), disabled all plugins, switched to the twenty twelve theme. Then was UNABLE to switch to another theme. Deleted and downloaded the twenty eleven theme and was able to switch to it, but then tried switching back to custom theme am now getting strange results: Chrome is loading the custom theme whereas Firefox, IE, OPera and Safari are all still loading the site in twenty eleven. Also tried adding the suggested line to wp-config.