Witnesses in a will

An unregistered will has no legal validity in the absence of witneses.

The main role of witnesses is to ensure that you have the mental capacity and intent to make a will. The Lawyer will ask "is this your will" in front of witnesses. The witnesses have the ability to observe you and your actions during this time. Witnesses are there to certify you have made the will, but they don't have to know the will's contents.

 A probate means a copy of the Will, certified under the seal of a competent Court with a grant of administration of the estate to the executor of the testator. It is the official evidence of an executor's authority. A probate is mandatory when the Will is executed by a Hindu, Christian or Parsi in the cities of Mumbai, Calcutta or Chennai, or pertains to immovable property situated in Mumbai, Calcutta or Chennai.

 A probate granted by a competent court is conclusive evidence of the validity of a Will until it is revoked and no evidence can be admitted to impeach it except in a proceeding to revoke the probate. However, it only establishes the legal character of the executor and in no way decides the title or even the existence of the property devised. The grant of the probate decides only the genuineness of the Will and the executors right to represent the estate.

I am sorry I was wrong interpreting when i replied earlier.It is not mandatory for a will to be registered. It can be implemented on a simple document and can be valued even if unregistered. Regarding witness of the will, if he dies the will is not as strong as it would be at the time of probate.