Nov 16 2021 05:01 AM
Nov 16 2021 06:14 AM - edited Nov 16 2021 06:15 AM
I guess it's ISOWEEKNUM that creates the problem. This function has been introduced with Excel 2013, so if someone with Excel 2010 / 2007 opens it, you are in trouble. All other functions should be uncritical.
You can replace it with WEEKNUM(TODAY(),21):
=IF(E17<>"",IF(AND(F17<>"",CELL("address")=ADDRESS(ROW(E17),COLUMN(E17))),WEEKNUM(TODAY(),21),IF(CELL("address")<>ADDRESS(ROW(E17),COLUMN(E17)),F17,WEEKNUM(TODAY(),21))),"")