Cannot view users

I hope this is not a unique problem. We imported 80k+ users into our wordpress user database, which is the front end authentication db for our CRM. Everything was ok, until last night when we updated all users from “role=none” to “role=subscriber” so that all users could post/reply on our bbPress forums.

NOTE: with role=none a user can login, but cannot participate in bbPress forum discussions.

So today, all users have ability to interact, but when we login as admin into wp-admin, we cannot view any users at all.