Have similar problem. Media Links fail in Mystile theme after WP 4.7 upgrade. 500 error. Generates error code:
20161214T185939: https://www.myannaart.com/wp-admin/admin-ajax.php
PHP Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 7680 bytes) in /hermes/bosnaweb03b/b2444/ipg.myannaartcom/wp-admin/includes/update.php on line 463
