“Shared Media” Tab is Not Displayed
First of all, let’s double check, that you are using the correct media library type. In order to do so, go to the plugin settings in network admin, which is the Settings > Network Media page.

You’re using the same library type as displayed on the screenshot, aren’t you? Great, but we needed to check that first.
It seems like you’re looking for a “Shared Media” tab in the wrong place.
Let me clarify this moment, the “Shared Media” tab is displayed when you’re:
- inserting an image (or other media types) into posts,
- inserting an image (or other media types) into custom fields or custom options,
- creating a gallery from images in posts,
- setting a post image or product images (if you’re using WooCommerce),
- etc.
However, the “Shared Media” tab is not displayed:
- when you simply visit the Media > Library page. This page displays the media files from the current site’s media library, as usual.
- if you’re already on the main website which represents the global library (it is a sub-site with ID=1 by default, but can be changed), in that case, try checking other sub-sites as well.