Mich. Comp. Laws § 600.6067
When the premises mentioned in any officer's certificate of sale of real estate under execution is not redeemed, the legal holder of the certificate is entitled to a deed therefor at any time within 10 years from the expiration of the time of redemption. Before any assignee or his personal representative shall be entitled to a deed, every assignment under which he claims title shall be executed and acknowledged or proved in the same manner that deeds are required to be executed, acknowledged, or approved, to entitle the same to be recorded, and the assignee shall cause them to be recorded in the office of the register of deeds in the county where the real estate sold is situated. When the deed is not taken and recorded in the time limited by this chapter, the certificate of purchase shall become null and void.
MCL 600.6067