Too many User Meta?

Hi, I’m trying to import content over to WordPress from a Drupal site.

This includes over 87,000 loyal users. However, if I attribute them all a status (in this case, “subscriber”), the user screen ends up blank. (No users listed)

If I trim it back down to around 35,000 listings in wp_user_meta, they reappear.

see screenshot here

Does anyone know what the problem might be?