In some states the beneficiaries of a will may agree among themselves as to the distribution of the property left to them and agree not to probate the will. This is the family settlement doctrine—and is supported by the general principle that the property belongs to the beneficiaries under the will and since they may divide the property as they wish (by transfers made immediately after the distribution), there is no reason why they may not divide it by agreement before they receive it in the regular course of judicial administration of the estate.

For this reason—and because such agreements tend to put an end to family controversies by way of compromise—family settlement agreements are favored in law. And in some states a family settlement in which all the heirs and beneficiaries agree that a purported will shall not be probated is valid and enforceable.

Thus, a will can be contested on the grounds that the person offering the will for probate (proponent of the will) agreed in a family settlement agreement not to probate the will.

In California, the concept of informal probate or family settlement agreements is recognized and can be a practical alternative to formal probate proceedings. Beneficiaries of a will can enter into a family settlement agreement to distribute the decedent's property among themselves without going through the court. This is often done to avoid the time and expense of probate, and to resolve potential disputes amicably. Such agreements are generally favored by the law as they can promote family harmony and provide a more efficient distribution of assets. However, it is important to note that all beneficiaries must agree to the terms of the family settlement for it to be valid. Additionally, these agreements must not violate any laws or public policies, and they should be in writing to ensure clarity and enforceability. If a family settlement agreement is in place, a will can indeed be contested on the grounds that there was an agreement among the beneficiaries not to probate the will. It is advisable for parties to consult with an attorney to ensure that the family settlement agreement is properly drafted and that all legal requirements are met.