Darrick,
Sorry for the trouble. Just to make sure I understand, you’re not able to add any new featured images and featured images that you’ve previously added are no longer visible in the box for them when you’re editing a slide, page, post, staff member or anywhere?
If that’s the case, then I would suggest disabling all of your plugins and seeing if you’re then able to interact with your featured images again. If you can, then turn your plugins back on, one by one, until they stop working. At that point you’ll know which one was causing the trouble.
If you’re having trouble uploading and assigning a featured image using the featured image box, then try this. Go to the Media section and select “Add New.” Upload your featured image there.
Then edit the page, post, or slide where you’re wanting to use that featured image. Click the link to add your featured image and then select it from your media library instead of uploading it there. Sometimes the new media library has trouble with uploading and then immediately inserting an image. Breaking that process into two steps sometimes helps there.
If you have any questions or trouble, let me know.
Thanks,
Bill