Mich. Comp. Laws § 38.1344

Sec. 44. Upon the separation from service by a member or upon the death of a member, a former member, a retirant, a retirement allowance beneficiary, or a refund beneficiary, any unclaimed retirement allowance or other money otherwise payable on account of the separation or death shall remain a part of that fund in which it is deposited until claimed by the separated member, retirement allowance beneficiary, or refund beneficiary or the estate or legal representative of a separated member, retirement allowance beneficiary, or refund beneficiary.