I upgraded to WP 4.5 today, and immediately lost my entire site. The initial page refresh with a "Success" message loaded up, but when it tried to refresh again so I could upgrade the database, it hung.
After that, I had only a browser error (Chrome) that said "mysite.domain.com did not send any data". Every page I tried to load crawled slowly, then eventually displayed that error.
I had to go to the server, disable all the plugins, then reenable them one by one. When I got to Events+, the site crashed again. I tried a few different plugin configurations, but it was always Events+ that brought back the same error.
Someone else reported the same issue today: https://premium.wpmudev.org/forums/topic/wordpress-45-update-with-events-crashes
My site is working now, but I had to disable Events+. I really need it working again, so I hope it can be fixed soon. Thanks.