I realize I can program around this with a ISBLANK, but there's hundreds of
examples like this and it will be an extremely time consuming and bug-prone
process to find them all.

So my question is really "why is this happening". If I put "=C120" into the
cell then it correctly puts in "". But if I use an IF to select one of the
two values, I get a "0". Is this a side-effect of the IF?

If so, is there some other way to choose between the contents of two cells
that doesn't have this side-effect?

Maury