I made an Excel addin that does time series calculations which is used
by a number of people in my company. It works by adding array
formulas to Excel for things like power spectrum

Sometimes, I will do some calculations and plot the results.
Everything looks fine. Then I save the file. When I re-open it I get
a "Not enough memory" error message from Excel. I click OK and the
file loads.

Graphs of the calculated data plot as zeros even though
1. the series point to the right place
2. the right place contains the numbers and array formulas.

If I force the addin to recalculate the data (in hte same place),
everything is plotted correctly!

If I remove the array formulas by copying and past special data only
on top of itself, the problem goes away permanently.

It's as if the workbook gets into some wierd state which is cleared by
re-running the calculations.

The normal F9 to force a recalc does not help.

I'm at a loss as to how to debug this one.