John, Bernard, Other MVPs who can bring light.... :)

I'm having this problem too and it makes no sense. I'm just selecting a
range of dates and a range of values to make a line chart. I'm a pretty
experienced user with VBA and advanced formulas under my belt and I've never
seen anything like this before. Has anyone been able to get to the bottom of
this. Most frustrating....!

FYI I have two workbooks open right now and seem to be able to chart fine on
one. In fact I can even chart data on other sheets in the affected workbook -
just one sheet seems to be affected.

Thanks for any help...