I have a workbook with a worksheet that gets refreshed
from a .prn file. Every 4 to 6 years there will be an
additional 2 columns for a week and then they will be
deleted.

I have formulas on another worksheet that refer to these
columns.

Anyone have any ideas on how to deal with this?
Of course once the column is gone I get an error in my
formula.

The .prn file is created by another program. I tried to
get the folks using that program to add those columns and
leave them there permanently (showing zeros when not used)
but apparently that is not possible. So I'm looking for
other ideas.

Thank you -
Sharon