Okay,Lets all chill out and come up with a method to help.
I am sure Frank is in panic mode.
Yes , There was a better way to handle this method. But that is the way it was done..
It is all behind us now.
The logs are so many rows it is hard to find what happened..

The longer we wait to resolve it the worse it gets.Due to new members registered and new posts.

My suggestion is if you have a backup prior to the 15,000 member loss then at the very least grab the :
ubbt_USER_GROUPS table and overwrite what you have in the active database
Restoring a 5gb database would probably be a huge chore.
That should restore all newbie groups except for new members since the date of the backup.
That should be a acceptable number to manually fix for registrations after that date.
It may not be clean but at least it won't be 15,000 members. to deal with
I don't know what host it is or what options there are.
but that is what I would start with.

Unless someone can come up with a easier way to get it fixed.

I still think it is a bug somewhat that allows you to move or delete groups in member management and leave them completely orphaned.. Even if it is operator error..

But it has been that way since the beginning days.
The hard part is once it is done the only way to find them by name is in the user list.
Member management will only find them by user ID# which is one at a time.

Sorry I did not jump back in the discussion
But I am preoccupied with a big magento store import to woocommerce right now so I am tied up for a few days..
.

Last edited by Ruben; 03/07/2019 4:09 PM. Reason: Added Comment

Blue Man Group
There is no such thing as stupid questions. Just stupid answers