Currently disabled the forum has had an attack and we now have over 170000 members, 99% of which are bogus. Is there a way to bulk delete them all by hacking into the database or table which has the members listed. Using the interface to dlete them would take about 8500 passes as I figure it which is not doable.
You can try this plugin: https://wordpress.org/plugins/bulk-delete/
Also, please read this topic, especially the #1 and #3 points:
Are those verified users (they have email verify their account) or just registered?
They did all verify all the emails which is what's wild, with askimet and wordfence installed and the captcha on. I set the forum to require manual approval from now on and was able to delete the users with the bulk delete plugin, although I had to go a few thousand at a time as more crashed the plugin so it took a while. But problem solved for now anyway, thanks so much for the init! 🙂