To me it looks like this behavior is the result of a recent Excel update as it only just started happening.Ĭreate Excel charts with trendline, error bars, data tables, data labels in C# using Spire.XLS The workbooks are protected and the charts produced are provided to clients and included in technical reports. I appreciate your interest, Sergei, as this is a serious problem for us because this occurs in workbooks that are used in a professional setting. So the problem occurs when the data for a Chart Range is all zero.

Then if I then undo these changes (the 0 entries), the trendline formula appears attached to the second Chart Range trendline as one of the other contributors mentioned (the formula can be deleted - but not on a protected workbook of course). If I then ender a zero into all the cells for row 4 to 6 the words 'Trendline Error' appears over the top of the left axis (and the second series all plots at 0,0): (The second chart in the workbook shows all the data plotted with a single series). The first chart in the workbook plots data from the table in two ranges with the first Chart Series plotting data from rows 2 to 4 and the second Chart Series plots data from rows 4 to 6. I have had a closer look and it is clear that the problem occurs when a Chart Series with a Linear Trendline plots data that is all zeros.

Power trend lines in excel 2016