A Will is a legal instrument through which the testator( the person who is making the Will) records his last wishes as to the devolution of his assets upon his demise. As per Section 18(e) of Indian Registration Act, 1908 registration of Will is not mandatory.
Though it is advised that you must get your Will registered to remove all doubts pertaining to ingenuity of the Will. However, registering a Will does not make it sacrosanct. It can always be challenged before the court of law. It is also not necessary that the registered will is the last testament of the deceased. A new Will made even though unregistered is valid and will have precedence over the registered Will. If there is any suspicion regarding the Will then it can be challenged before the court.
Here a few grounds for challenging a registered or unregistered Will -
1. Undue Influence - Undue influence refers to a situation where by you are induced to act in a certain way which is against your own free will or without having adequate consideration of the consequences. If a Will is made under undue influence it is considered as bad in the eyes of law and can be challenged before the court.
2. Fraud - If a person is deceived to make a Will then that can also be challenged before the court. Such a Will is considered not made by the free consent of the testator and it can be revoked by the court.
3. Coercion - If a Will is made because someone persuaded you using force or threat then such a Will is invalid and can be nullified by the court.
4. Lack of proper execution - A Will needs to be duly signed by the testator. Along with the signature of the testator, the Will must contain the signature of at least two witnesses who have seen that Will has been made by the testator. If any of these requirements is missing then it is said that Will is not valid.
5. Lack of testamentary capacity - The person making the Will shall understand the nature and consequences of making the Will. He should absolutely understand to the extent the property that he is disposing of and should be mentally fit.
6. Revocation - After making the Will, the person can revoke it himself if he or she isn't satisfied with what he has made. Revocation of Will make it invalid and is no longer considered enforceable.