Can't add featured image

Hello everybody,
i have update my wordpress to 4.4.
But when i want to add or edit a post, featured image settings doesn’t appear.
All my post use a featured image, and it’s work fine but i can’t add or edit featured image in the admin panel.
I have try to downgrade to 4.3.1 and to desactivate all plugins but nothing change.
My theme is Me Gusta 3.2 from themeforest.
Can you help please ?

Thanks in advance !