A will may be invalidated by the probate court if it fails to follow the requirements set by state law, like those regarding who can write a will, how the will should be constructed, and how it should be executed. An essential estate planning document, a will can be legally valid even when it’s not registered, filed, or notarized.
Every state has its own set of legal requirements for a valid will, and failing to follow even one could mean trouble for your estate. If a will is ambiguous, poorly constructed, or written under suspicious circumstances, someone may try to contest, or challenge, it upon your death and have the will invalidated by the court during probate. When a will is deemed invalid, it’s almost as if you died without a will at all, since the court may need to determine who receives your assets and property.
A will must be written according to your state’s legal statutes, and you can even make a valid will without a lawyer. Some states also place an age requirement on who can write a will, like the testator must be the age of the majority or older. A will written by someone under age would not be valid.
Failing to sign and witness a will
It's essential that you sign your will, unless you are physically unable to make a signature. State laws usually provide a way to have someone else sign in your stead if you physically can't sign.
A will is invalid if it is not properly witnessed or signed. Most commonly, two witnesses must sign the will in the testator's presence after watching the testator sign the will. The witnesses typically need to be a certain age, and should generally not stand to inherit anything from the will. (They should typically be disinterested witnesses).
Learn more about witnessing a will.
While witnesses are required for a will to be a valid legal document, notarizing the will usually is not — unless you want to make the will self-proved.
Lacking testamentary capacity
The validity of a will also hinges on testamentary capacity, or the mental capacity needed to write a will. The testator needs to understand the stakes and nature of the document: what a will is, how the will disposes of property, what property and assets they own. Someone may try to contest a will if they believe it’s been written without testamentary capacity, such as during a delusion or even a drunken stupor.
Learn more about testamentary capacity.
Undue influence & fraud
Undue influence happens when a person coerces the testator into creating and signing a will against their wishes. The influencer usually benefits from the will, and they have to do more than suggest the testator add them to their will — they put the testator under immense pressure so that they feel like they have no other choice but to comply.
Fake wills or forged documents are never considered valid. Neither are fraudulent wills, which might result if someone tricks the testator into signing a will by pretending it’s a less important document.
In one notable example, after famous tycoon Howard Hughes died without a will, a handwritten one was brought to light but it was deemed a forgery and invalidated by the court. Read about more high-stakes disputes over celebrity wills.
Having multiple wills
If you die leaving behind multiple wills, there may be questions as to which one is valid. When you update your will with a codicil or make a new one entirely, make sure to destroy the older versions to prevent confusion. If you filed your previous will with an attorney or your local county court, don’t forget to give them the most updated version, too. (Not all states allow you to register a will during your lifetime; filing a will is usually for safekeeping and storage and doesn't have any affect on the will's validity.)
To further ensure your new will is valid and passes muster in court, you can also include a provision in it that revokes any previous wills that came before, just in case they come to light after you pass away.
Related article: What you should never put in your will
Contesting or proving an invalid will
Having a will declared invalid can be difficult, depending on the circumstances. The probate court may easily recognize that a will is invalid based on construction when it fails to comply with the state law — like when the will is forged in someone else’s handwriting. However, proving that a will is not legally valid because of a lack of testamentary capacity or the presence of undue influence, typically requires the person contesting a will to provide proof to the judge. That means you will likely need evidence or witness testimony about the testator’s state of mind and circumstances when they wrote the will, which may have been years ago.
For this reason, contesting a will can be costly if you end up seeking legal advice from a probate attorney, and it can ultimately delay how long it takes for the estate to be settled and anyone to receive an inheritance.
If you're worried about someone contesting your will, you might consider including a trust as part of your estate plan. A trust distributes assets according to the terms you set out, apart from the will and outside of the probate process. In fact, assets in a trust can be passed to the beneficiary even as someone is contesting your will. (Read about how living trusts and wills work together.)
What happens when a will is invalid
The court may need to step in and decide who your beneficiaries are when a will has been invalidated. Each state has intestacy laws, which determine the deceased person’s heirs when there is no will, and they can apply in the case of invalid wills, too. Typically a surviving spouse has legal right to inherit some of the intestate estate.