I was using the MultiCharts.cpp example and it worked fine at first. I then changed the cell count to 15 and added my own data. This is the main code I changed. CorrelArr is full of doubles. const int DataCellCount = 15; // fill data sheet with randomly generated numbers for(int i = 0; i < 15; i++) { cellDbl.value = correlArr[i]; data1.push_back(cellDbl); cellDbl.value = correlArr[i]; data2.push_back(cellDbl); } FirstDataSheet.AddRow(data1).AddRow(data2); // data can be added by row or by cell //...