It would be good if this error could be handled to avoid this error but I had no luck with doing this
problem is the function is called for every row. You could just disable the msgbox - but then the developer won't necessarily know there is an error. And there is nothing like being constantly reminded to ensure you don't forget in the future
I'll take a look at your serialise function.
With regards group number I can see plenty of situations where could be useful - lists of invoices/lines, customers/invoices, products/transactions, products/versions, transactions by period to name but a few.