Michigan Compiled Laws, Chapter 700. Estates and Protected Individuals Code § 700.3303

Sec. 3303. (1) In an informal proceeding for original probate of a will, the register shall determine whether all of the following are true:

(2) The register shall deny the application if the application indicates that a personal representative has been appointed in another county of this state or, except as provided in subsection (4), if it appears that this or another will of the decedent has been the subject of a previous probate order.

(3) A will that appears to have the required signatures and that contains an attestation clause showing that requirements of execution under section 2502 or 2506  2 have been met shall be probated without further proof. In other cases, the register may assume execution if the will appears to have been properly executed, or the register may accept a sworn statement of a person having knowledge of the circumstances of execution, whether or not the person was a witness to the will.

(4) Informal probate of a will that was previously probated elsewhere may be granted at any time upon written application by an interested person, together with deposit of an authenticated copy of the will and of the statement probating it from the office or court where the will was first probated.

(5) A will from a place that does not provide for probate of a will after death and that is not eligible for probate under subsection (1) may be probated in this state upon receipt by the register of a properly authenticated copy of the will and a properly authenticated certificate of its legal custodian that the copy filed is a true copy and that the will has become operative under the law of the other place.