Thank you to user “crscrk” who provided this:
WordPress 4.5 broke my ability to upload media to my photo journal travel blog just as I was packing for a month long out-of-country trip- I kept getting an http error. There’s quite a conversation about it amongst many affected. I simply rolled back to the previous version of WordPress and didn’t lose a thing, even my most recent posts. Thank you UpdraftPlus for having my back!