Forum Discussion
Excel inserts '@' Symbol into formulars, which breaks them
It would appear to be an error introduced in an attempt to achieve compatibility with legacy Excel.
Your formulas specify that each array is precisely 1048576 elements long and the natural implementation of the formula in old Excel would be a set of CSE array formulas over entire-column arrays.
Many Excel functions used to recognise that the calculations need not extend beyond the Used Range, but the combination of entire column references and array formulas could work out very badly in terms of performance. It seems that Excel has protected you from one problem but at the expense of invalidating your formula!
It may be that moving away from old-school entire column references to adopt the 2007 practice of using Excel Tables (or accurately sized defined Names) would bypass the problem.
JoeMcDaid should possibly get someone to check whether your problem should be considered to be a bug and, if so, whether solving it would cause more problems than leaving it.