I needed to check for duplicate attachments in a system and remove the duplicates. I created a Job that used the same origin and destination and pulled all records from the Attachments table. I had a before operation that would read and write to the same xref list. In this code, I check to see if the record I'm reading already exists in the XREF. If it exists, then I know it is a duplicate and can proceed to the Delete Stage. If it does not exist, then it is not a duplicate and I write the data to the XREF and skip the Delete Stage.

Sub VBScriptProcedure
 dim strExists
 strExists = xrefread("sf-attachments","@@ORG:ParentId@@@@ORG:NAME@@")
 If strExists = "Exists" Then
  LogMessage "Duplicate of: @@ORG:NAME@@"
 Else
  XrefWrite "sf-attachments","@@ORG:ParentId@@@@ORG:NAME@@","Exists"
  GoToNextRow
 End if
End Sub