I had a problem updating, so I disabled my plugins using the FTP method: change name of plugin folder to plugin.hold, create new (empty) plugin folder, then once updated, delete new plugin folder and rename “plugin.hold” to just “plugin” again. That made it possible to update WP. But once all of that was done, I saw the same problem you have – my home page was missing lots of elements. When I looked into why, I noticed that all my plugins are inactive. And it will not let me activate them. I’m looking for a post with this exact problem, but If I don’t find it, I will open a new thread. I just wanted to share with you in case your problem is related.
