Just taking a guess... maybe A2:R2 contains cell(s) towards the end that contain formulas that return "" resulting in your lookup formula returning "" and you are thinking that it is not returning anything?Can anyone explain why this formula works:
=LOOKUP(REPT("z",255),A2:A10)
And the one below doesn't work?
=LOOKUP(REPT("z",255),A2:R2)
In advance, thanks!