Hi FDibbins, I am looking for a reason why they don't work when the referenced file is NOT open I have several examples of files where SUMPRODUCT works fine even when the referenced file is NOT open so I don't know why these ones don't - this is the main reason I use SUMPRODUCT as I want to keep my data separate from my dashboard but I don't want the user to have to have the data sheet open, only the dashboard.