I've seen a handful of people with this exact same issue but nothing I found fixed the issue for me.
I’ve recently created a new WordPress on localhost (wordpress 4.7 on wampserver, windows) with a child theme running off of twentyseventeen main theme. I can access the site itself and the admin dashboard however when I try and access the media library, the loading spinner just keeps spinning and never loads the library.
From within a page/post/library I can upload a media file but get an error on the front end of the dashboard: ‘An error occurred in the upload. Please try again later.’
If I look in the uploads folder the image is there along with all size variations.
I also can’t search for a plugin, when I enter a search term it just keeps showing the loading spinner and nothing ever happens.
Another user had the same issue but said changing the .php file encoding to utf-8 with BOM fixed his issue. I tried encoding all to utf-8 with and without BOM but neither worked.
Someone has to have been able to fix this issue, any ideas?