All my forums require registered users.

I noticed the other day that a thread showed a unregistered user had posted. I thought reindexing would clean it up later and didn't think much of it.

Now a user contacted me saying, why did I delete his account.

I checked his account and it was fine and let him know that.

Then he explained all his posts that he previously did are showing as unregistered.
And he can't log on.

So I did a Reindex and clear all cache.

Then I go and look at his account again and it's gone !

I'm the only moderator of the entire system.

How can I recreate his account using his old ID?

Any ideas what can cause this?

Classic 6.7.2 running on linux servers.