No snippet preview and no meta description after upgrade

I had the same issue that I couldn’t save meta description. Rolled back to v3.0.7 and it’s working.

The error is possibly due to the lack of the slugdiv meta box on either single Post or Page admin views. This might be unset as the result of a plugin like Advanced Custom Fields, or it may be due to some other custom code:

remove_meta_box('slugdiv', 'page' , 'normal');

I frequently remove it, to make the admin pages cleaner for clients. If you are getting a JS error traced back to wp-seo-post-scrapper.min.js then this is likely your problem. The script relies on an input field in the slugdiv container to write to it’s own hidden fields.

i just disabled WP Edit and it restored the boxes.

Check your plugins for anything that affects your editors ??