In most states, if a person dies without a Will or if his Will is totally invalid the result is complete intestacy. This means the entire estate of the deceased will be decided by the court under the rules of the forum state.
Intestacy is partial if the testator made a Will but not all of his property is disposed of by the Will. This can happen when the Will does not contain a residuary clause or a residuary heir disclaims his interest. Any such property will pass under the laws of intestacy as described above.
A testator may prevent an heir from taking by intestacy by simply disposing of all his
property by his Will. However, if a Will does not dispose of all his property, the heir may take by intestacy. Also, in most states a Will may not completely disclaim a spouse or minor children under "Elective Share" statutes.