Hi Neg~,

Ignatius is right, it only seems to happen with Excel 2007. I have also tried it with Office 97, 2000 and 2002 (XP) and it doesn't work. I didn't think it was worth going back to Office 4.3 as it seems to be something new?

I have no idea why it happens, as it seems to be based on the result 65,535. Perhaps Mel could shed some light on this as it is way beyond my feeble math?

It seems to happen with a variety of processors as well, so it doesn't look like that funny floating point arithmetic problem that there was with early Pentiums, or the modern equivalent.