Compiled Laws, Chapter 168. Michigan Election Law § 168.503

Sec. 503.If the voter registration records are destroyed or mutilated making them unusable, the clerk of the city or township shall request a back-up file from the secretary of state. The secretary of state shall provide a list of registered electors and their signatures, if available, from the qualified voter file to the city or township clerk. If the secretary of state is unable to provide a back-up file to the city or township clerk, the clerk shall require the electors to reregister as prescribed by the secretary of state.