Prototypes are supposed to be thrown away; the point is to learn &amp; validate, not to serve as the basis for a commercial product.  So the obvious solution is to <i>throw it away</i> and start from scratch with code that&#x27;s written only by people with clear IP assignment agreements to the company.  Then, legally, at least you&#x27;re in the clear; IP is usually construed as code&#x2F;documents&#x2F;etc, and just because you once worked together on a project in a vaguely similar space doesn&#x27;t mean that they have any claim on future output.  You can&#x27;t stop them from <i>suing</i> you (anyone can sue anyone for any reason), but you can stop them from <i>winning</i>.<p>Socially, your best defense is to make it clear at the end who&#x27;s interested in turning it into a startup and who&#x27;s not, and extend the invitation to join as cofounders to anyone who&#x27;s committed to it.  If you liked working with them as people (and that&#x27;s part of the point of these programs), you lose nothing from doing this anyway.  If you didn&#x27;t like working with them, chances are you won&#x27;t have anything of value anyway, but that&#x27;s where you throw away what you&#x27;ve got and start fresh.