Hi,
Still having problems. The function that adds the new record to the table now checks whether the unique key already exists by using the seek function. Despite this the problems are still occurring.
I was wondering whether duplicate ip addresses on pc's might have something to do with it but I'm not sure exactly why or how, I'm just clutching at straws.
I have been reliably informed that the problem never used to occur before we moved over from a Novell network to NT. Can you think of any reason why moving over to NT might cause a problem?

Phil.