When Is a Will Not Valid? 10 Common Situations Explained


Attorney, distinguished law professor

Although a will can be simple to write, there are many rules to follow in order to execute a will that is legally valid. These rules can also vary from state to state. The laws for wills are usually strictly enforced, and if you do not follow them, the court may declare your will, or any part of your will, to be invalid.

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Typical Situations Where a Will May Be Invalid in the US

There are two categories of rules for wills, known as “formalities” and “intentionalities.” “Formalities” are those rules that are required for the proper execution of your will. These typically involve:

  • Signature
  • Witnesses
  • Presence

By contrast, “intentionalities” are the rules related to your state of mind at the time you signed your will. These can involve:

  • Testamentary capacity
  • Testamentary intent
  • Delusion
  • Undue influence
  • Fraud

The court will not address issues of intentionality unless it first determines that all the formality rules have been satisfied. If your will is invalid because it was not executed properly, then it doesn’t matter what you intended.

You also can invalidate a valid will by revoking it. Just as there are rules for executing a will, there also are rules for revoking a will. If these rules are not followed, the court may declare a will to be valid that you really intended to invalidate. 

Here are ten ways in which a will can be invalid based on formalities, intentionalities, and revocation.    

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1. Lack of testamentary capacity

To have a valid will, in addition to being of proper age (usually 18), you must have proper testamentary capacity. This means that you must be of “sound mind” at the moment you execute your will.

To be of sound mind, the testator must be aware of:

  • Their property
  • The natural objects of their bounty
  • The nature of their bequest   

Understanding one’s property means understanding what assets you own in your estate. For example, should someone write in their will that they want to give the Brooklyn Bridge to their children, falsely believing that they possess legal title to the Brooklyn Bridge, this is evidence that the testator does not understand what property they own. As a result, this may be considered as a sign that they may lack the mental capacity to execute a valid will.

Similarly, to understand the natural objects of one’s bounty, the testator must understand who their closest living relatives are. If someone does not have the mental capacity to know and understand who their relatives are, they probably are of unsound mind and cannot legally execute a valid will.

Finally, to know the nature of their bequest, the testator must understand that they are signing their last will and testament and what the consequence of signing it will be. For example, if a testator signs a will thinking they are actually signing a lease for a home, they do not have sufficient mental capacity to execute a valid will.

If they do not understand that by signing their will, the persons named in the will are going to inherit their property when they die, again, they do not have sufficient mental capacity to execute a valid will.

2. Lack of testamentary intent

A will also can be invalid if, at the time the testator signed the document they did not intend for that document to serve as their final last will and testament. If someone signs an incomplete draft of a will, knowing that the document as written does not represent what they intend to be effective as their final will, then the will could be invalid.

3. Lack of a proper signature

Most state laws require the testator’s signature to be in the testator’s own handwriting. For most, this means writing your full name. However, there are often cases in which the testator’s signature is not in their own handwriting. For example:

  • The testator may ask someone else to sign their will for them (this is called a “proxy” signature)
  • A testator may sign their will by holding the pen while someone else writes the testator’s name by moving the testator’s hand across the signature line (this is called an “assisted” signature)    

In these examples, if the state requires that the testator’s signature be in their handwriting and does not expressly authorize “proxy” or “assisted” signatures, then the wills with these signatures may be invalid. However, there are many states that expressly authorize proxy and assisted signatures.

There are also cases in which the testator does not sign their “fully intended signature.” For example: 

  • In a letter to his children in which he explains how he wishes to dispose of his property at death, a father may sign the letter “Dad” rather than his full name  
  • A frail and elderly testator may begin to sign their name but feel too weak to complete their signature, leaving only their first name on the will
  • A testator may simply write an “X” on the signature line of the will

In all of these cases, the signature will be invalid if the testator did not intend for what they wrote to complete the execution of the document. These signatures may serve as a valid signature, however, if what the testator signed is normally what they write when they sign documents. 

No matter how a testator signs their will, the signature must satisfy the state’s rules and be one that the state recognizes as valid.

4. Lack of proper witnesses

Every state requires a will to have a specific number of witnesses. There are two ways for a will to be invalid based on a lack of proper witnesses.

  • Insufficient number of witnesses. Every state requires that a will have at least two witnesses. If you only have one witness, then the will may be invalid.
  • Witnesses are not disinterested. A state may require both witnesses to be “disinterested.” This means that the witnesses cannot also benefit from the will. If they do, they may not count as one of the two required witnesses. However, they still can  serve as a witness if there are two other disinterested witnesses.

Some states will allow witnesses to benefit under the will. Others allow for interested witnesses but limit the amount they receive from the will to what they would have received through intestacy if the will were invalid. This removes any incentive for a witness to falsely testify to the validity of a will.      

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5. Lack of proper presence

Every state requires that the testator sign the will in the presence of witnesses. But “presence” can mean different things in different states. In any given state, signing in the “presence” of a witness could mean any of the following:

The testator and the witnesses each see each other sign (known as the “sight” test):
  • The witnesses see the testator sign
  • The testator sees the witnesses sign
  • The witnesses see each other sign
The testator does not actually see the witnesses write their name on the will.

The testator may however be conscious of what is taking place when the witnesses sign (this is called the “conscious presence” test).

  • The testator may sign in the presence of one witness and, within a reasonable amount of time, acknowledge their signature to a second witness (so the witnesses do not have to be present at the same time)

Whatever the rule for “presence” is in your state, you must be sure to follow the rule or your will may be invalid if someone contests the will on this basis.

6. Insane delusion

Some states will invalidate a will, or part of the will, if it is shown that the testator was suffering from an insane delusion at the time of the execution of the will. For example, a testator may disinherit their spouse in their will because they believe their spouse was unfaithful during their marriage.

The spouse may contest the will by claiming that the testator spouse was suffering from an insane delusion that affected their disposition of property in the will.

In most states, to prove that the testator’s delusion was an insane one, the spouse must show that even though there are facts to support the testator’s belief, no reasonable person would have concluded what the testator concluded.

However in other states, if there are any facts that support the testator’s belief—no matter how unreasonable they may be—then the delusion is not an insane one, and the will may not be invalidated on that basis.

7. Undue influence

For example, someone can unduly influence a testator to dispose of property in a way that benefits them alone. If it can be shown to the court that there was undue influence on the testator, then the court may invalidate the part of the will that benefits the person.

This issue often arises when someone takes advantage of a vulnerable person and convinces them to change the disposition of property in their will to benefit them, and the testator’s relatives object.

A typical scenario of undue influence occurs when:  

  • The testator is particularly vulnerable to influence because they are elderly, frail, ill, disabled, or are in some way dependent on a caretaker.
  • Someone (often a relative) who normally is not involved in the testator’s life suddenly steps in to care for the testator.
  • The caretaker moves into the testator’s home or now has regular contact with the testator.
  • The caretaker convinces the testator to include them in their will or to exclude others from their will.

If a testator had a history of wills and codicils (supplements to wills) that consistently benefitted particular relatives but then suddenly changed their will to benefit someone else who recently had the opportunity to unduly influence them, then the portion of the will that benefits that person may be invalid.  

8. Fraud

A will, or a part of a will, may be invalid if someone benefits from the will by defrauding the testator. This occurs when someone makes a false statement to the testator, intending for the testator to draft or amend their will in a way that benefits them or excludes someone else.

For example, if one sibling falsely tells a parent that another sibling is using drugs with the intention that the parent will omit the other sibling from their will, and the parent is actually defrauded by the misrepresentation and changes their will, then the portion of the will that resulted from the fraud may be invalid.

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9. Revocation

An otherwise valid will can be invalidated by a testator revoking the existing will. There are three ways to revoke a will:

  • Physical act (tearing, burning, destroying, writing on, crossing out, obliterating, or other actions)
  • Subsequent instrument (executing another will in which the testator expressly revokes a previous will, making it invalid)
  • Operation of law (when any portion of a will is automatically invalidated upon the occurrence of an event, such as when a will benefitting a spouse is automatically invalidated upon the spouses’ divorce)

10. Lost will presumption

Someone can claim that an existing will cannot be produced because it is not found where the testator was known to keep it. As a result, the court may presume that the testator intended to revoke the will and not that the will was lost or misplaced, and deem the will to be invalid. 

What Happens If a Will Is Declared Invalid?

If a will is invalid and there is no other will, then the testator is said to have died “intestate.” This means that the testator’s property will pass through “intestacy.” When this happens, the court will award the property to the testator’s closest living relatives, as determined by the state’s intestacy laws. If this is not how you want to dispose of your property, you must be sure that your will is valid.     

How Can You Prove That a Will is Invalid?

Someone with an interest in the testator’s estate (for example, an heir who will inherit part of the testator’s estate if the will is determined to be invalid), may contest the validity of the will in court and ask the court to invalidate the will.

To succeed, they must raise one of the ten claims discussed above and present evidence to the court, demonstrating that one of these scenarios occurred. If they cannot support the claim, the will may be probated. 

Follow the Rules to Create a Valid Will

There are a lot of rules to follow if you want to have a valid will. This means that there are a lot of ways to make a mistake. However, every state provides instructions for creating a valid will in its Probate Code. If you want to have a valid will, you should read the instructions or have an attorney explain the instructions to you.       

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