I use Seek() to see if a record is found. If it is I change the as as necessary, if not I use Insert Into to add the record.

I ran into the problem were the record could not be found and the Insert Into code generated an error that indicated creating this record would violate the Uniqueness index.

Comes to find out the index file had to be REINDEXED. This solved the situation. However, how can this situation be trapped and the user warned that all is not well?