Undeletable posts, users or other content

When I see behavior like this, it’s almost always a corrupt MySQL table or two. You can activate WordPress’s built-in repair tool by adding define( ‘WP_ALLOW_REPAIR’, true ); to your wp-config.php file and visiting {$your_site}/wp-admin/maint/repair.php You can remove the define after you’re done.

WordPress Visual Editor is not working

One reason why it’s not working would be the using a old version of Visual Editor in a newer version of WordPress. So, you have two choices now either downgrading WordPress or upgrading Visual Editor. Give it a try, Hope it might work for you.