Undefined index: authorship

I’m getting the same notice when trying to add a post, page or custom post type

Notice: Undefined index: authorship in /Applications/MAMP/htdocs/phpLocalhost/wordpress-artlense/wp-content/plugins/wordpress-seo/inc/class-wpseo-meta.php on line 451

Notice: Undefined index: type in /Applications/MAMP/htdocs/phpLocalhost/wordpress-artlense/wp-content/plugins/wordpress-seo/admin/class-metabox.php on line 694

double post, sorry. Please delete this one

+1 for having the same issue. Using Yoast SEO version 1.6 and WordPress 4.0.

Temporary solution until we hear back from plugin author:

Go to php.ini file and search for
zlib.output_compression = on

Turn it off:
zlib.output_compression = off

Note: The zlib extension offers option to transparently compress your pages on-the-fly so we need it in future.

Yeah, got the same problem. Hope the de plugin author will fix it soon.
Using also Yoast SEO version 1.6 and WordPress 4.0

Same here, but with two more error messages. This happens when creating a new page.

Notice: Undefined index: authorship in  ../wp-content/plugins/wordpress-seo/inc/class-wpseo-meta.php on line 451

Notice: Undefined index: type in ../wp-content/plugins/wordpress-seo/admin/class-metabox.php on line 694

Warning: Cannot modify header information - headers already sent by (output started at ../wp-content/plugins/wordpress-seo/inc/class-wpseo-meta.php:451) in ../wp-includes/option.php on line 750

Warning: Cannot modify header information - headers already sent by (output started at ../wp-content/plugins/wordpress-seo/inc/class-wpseo-meta.php:451) in ../wp-includes/option.php on line 751

Fresh WordPress 4.0 installation with a couple of plugins: WordPress SEO 1.6, WPML 3.1.7.2 and WPML String Translation 2.0.9.1.

For me this isn’t something criticaI I need to get fixed right now, but I guess it’s good the Yoast team knows something’s wrong.

Version 1.6.1 was just released and it fixed the problem for me. Thanks Yoast.

Yep, version 1.6.1 has fixed the problem!

Yes version 1.6.1 also fixed my issue.