‘Warning: Class __PHP_Incomplete_Class has no unserializer in /home/content/p3pnexwpnas07_data02/37/2743037/html/wp-content/object-cache.php on line 520’ is the error I get too! I’m on GoDaddy managed WordPress hosting and will call them about this to see what a deep cache flush on the back end will do. The error seems to go away when I deactivate my plugin Better WordPress Minify but that my be a coincidence since that plugin affects/interacts with the cache of the site (as far as I understand). Anyone else running this plugin?