Well, preferably, before the dispute happens.  And if the parties have done so, hopefully there’s an agreement in place that will map the outcome of that dispute.

But in the real world, oftentimes that’s not done.  Then a lawyer should be contacted as soon as possible, even when a shareholder senses that there’s a problem, because oftentimes we’re, as shareholders, too emotionally attached to be able to step back and find a solution before that problem blossoms into something bigger.