I have an issue where I've used VLOOKUP in Excel, and the source table is regularly modified with the addition of a new column, which prevents my lookup from functioning correctly.
Is there a question embedded in that statement? Obviously less than desirable, but what are you seeking in posting that description? What's your level of involvement with the source table other than using it in VLOOKUP? Do you have any say over how it's maintained/modified? Could you have?