I believe we are having the same issue. I noticed a new message on our plugins page: “The plugin custom-post-type-maker/custom-post-type-maker.php has been deactivated due to an error: Plugin file does not exist.
Up until a couple of hours ago the custom posts were still working fine. About an hour ago we noticed that on our live site, when we type in or click on a link to a custom-post-type post, we get redirected to the home page. On our dev site we get a 404 error. When looking at the dashboard, the custom post entries were not displayed either.
For instance, we have a post type “video-library” which displays embedded videos. Usually it is listed just below “comments” on the sidebar of the admin page, but it is not showing. And clicking on a video link does not work. Example:
https://saclaw.org/video-library/guardianship-screencast-part-1-introduction/ is a link to a post with a video on guardianship embedded. But clicking on it brings us back to the home page.
I reactivated the plug-in on the dev site and the post types are displayed on the sidebar again, [and the posts themselves are still there, thank goodness] but still give a 404 error when I try to navigate to them either via clicking links or typing them in directly.
As far as I know nothing was changed on the live site this afternoon. On the dev site I was tweaking the search results page template but nothing else.
The only thing that looks a little iffy is that we have not updated WordPress to 4.7.2.
Unfortunately when I disabled all plugins except Custom Post Type Maker, the entire site refused to load.
We do use a custom theme built for us, so if this doesn’t resolve we will contact the designers.
Thanks for any input!