When a person dies with or without a will, his or her estate will need to be administered appropriately. Someone may prove (probate) his or her authority to deal with all of the assets and liabilities of the deceased person. This might involve a will or not. It might involve a court application, or not.
If there is a valid will the process should be more regular and predictable. In any case, the law provides rules and procedures designed to resolve uncertainties and settle disputes.
A number of troublesome issues may arise. Maybe there is no will. Perhaps a will is found, but it is defective. Possibly, the will is incomplete. The will may even have been obtained under suspicious circumstances, by exercise of undue influence or, when a person was not competent. The list of such potential issues is long. Achieving a satisfactory resolution, through normal administration, mediation or litigation will require proper analysis and correct decisions.