Lovely that these tips work for everyone but not for me, so thought I’d share. I couldn’t update my plugins (Jetpack and SEO Yoast) after update to WP 4.2. I de-activated all plugins and tried to update while deactivated. I also tried the modification to wp-admin/includes/file.php via
https://core.trac.www.ads-software.com/ticket/32135.
What I ended up doing – deleting the two problematic plugins and manually re-adding them. Now I’m good to go.
