Excel goal seek doesn't go through a macro

Hello,

I'm trying to use the goal seek function of excel to seek out a particular value of a cell (say Y) by changing values of another (say X).

Problem is, Y is arrived at through a macro that runs when X changes, and not simple Excel formulas.

When goal seek runs, although it keeps changing the X values while looping, the changes don't reflect on Y and thus it can't find a solution.

Goal seek works perfectly if I remove the macro and write (a short and simplified version of) Y using formulas. But I need the macro to have Y right.

Any ideas?

Regards,
Mrunmoy