Custom Post Type 20k posts = blank/404 within Admin Edit.php

Hi,

I have registered a custom Post Type, and about 45 Custom Fields (via the appropriate metabox function) within the theme.

Everything works fine there, and a few tests by manually creating posts via the Admin Editor for this post type proves such.

I written a script to batch import about 20,000 or more into this custom post type and the registered custom fields. Before I go on, I wish to point out that I first ran this script with just 50 or so of the entries, and it imported and everything worked fine.

So, once the 20k posts of the custom post type were imported, I return to my admin and hit on the Custom Post Type via admin (Auto-generated Custom Post Type UX) – and I receive a blank page!

I have resrearched, and as a result increased PHP memory limit, WP memory limit, WP Max memory limit, and PHP execution time. After which, I now receive the generic WordPress 404 instead of just a blank page. I cannot get past this.

Here’s what I added to wp-config.php:
define( ‘WP_MEMORY_LIMIT’, ‘256M’ );
define( ‘WP_MAX_MEMORY_LIMIT’, ‘2560M’ );
set_time_limit(120);

Please help!

Thanks in advance!