California Code, Probate Code - PROB § 11850

(a) The property remains in the possession of the personal representative unclaimed or the whereabouts of the distributee is unknown.

(b) The distributee refuses to give a receipt for the property.

(c) The distributee is a minor or incompetent person who has no guardian, conservator, or other fiduciary to receive the property or person authorized to give a receipt for the property.

(d) For any other reason the property cannot be distributed, and the personal representative desires discharge.  Notwithstanding Section 11851, deposit may not be made under this subdivision except on court order.