If you experience that after uploading media items are not showing in the Media Library while physical files were copied into the upload folder, the following instructions should fix the problem.

  1. Open the Access Viewer.
  2. Ensure that the Inherit checkbox is set for the Masters node for the sitecore/anonymous user.
  3. The sitecore/anonymous user should have all allowed security rights for the whole media library.
  4. Check also that the Everyone group has the same security setup.

I.e. this user (sitecore/anonymous) should have rights for the Media Library where the items are created and for the masters the media items are created from since these actions are performed under this account.