[chrishajer]

I don’t know the answer to the BIGINT and 32 bit signed stuff, but I do know this has happened before, sort of. Maybe this will help you sort it out. Basically, you need to reset the auto_increment user id to something sane. In the past, it happened on conversion from phpBB I think.

https://bbpress.org/forums/topic/user-id-999999999