Legal Question in Real Estate Law in California

You absolutely cannot foreclose on an unsigned, unrecorded deed of trust. If the trustor never signed it, you have an unsecured loan. You theoretically could go to court and establish that you had a right to the deed of trust and it was somehow forgivable error that it was never signed and recorded. But by the time you do that, you would have done the same thing as if you just got a judgment on the unsecured debt, and then filed a judgment lien. And that's a far better and easier case than trying to get the deed of trust established by court order.