Hi, I'm new to this forum and new to Excel. I'm on Mac 10.3.9 using Excel 2004.

I'm making a chart by selecting 12 cells (one for each month) which use formulas (simple sums) and are not next to each other. I can get up to ten of them to go into a new chart using the chart wizard button. But if I select all twelve I get the dreaded message, "Your formula contains an invalid external reference to a worksheet."

I have no idea what that means.

I've tried manually typing in the data range of the edit box for the chart, but what I type literally won't show up in the data range entry line beyond a certain point. Wierd.

I'd appreciate any ideas from you more experienced Excel folks.

Thanks.