>I can always APPEND BLANK one record to the cursor without an error. I then populate that record with values, in particular with GroupID and VisitID. If GroupID = 1, I can append additional records, populating each one before appending the next one without errors. However, if GroupID = 2, I can APPEND one record. When I attempt the next APPEND BLANK it triggers the index uniqueness violation error.

Jim - try putting the index key expression into the Watch window and see what the value is when you succeed and when you fail.

Tamar