An invalid will

Statistics show that as many as 45% of people who die either have no Will or an invalid Will.

Dying without a Will or an invalid Will is called dying intestate. 

The main consequence of dying intestate is you don't decide how your assets are distributed.

Each state/territory government in Australia has established a procedure to follow for dividing assets if someone dies without a Will. This procedure varies according to the deceased's circumstances - in particular, where they are domiciled, where their assets are located and whether they are married and have children. In some jurisdictions, the size of the estate also affects the distribution of assets.