In Herald Co Inc v Eastern Michigan University Board of Regents, 475 Mich 463 (2006), the Michigan Supreme Court clarified the standard of review for FOIA cases:

First, we continue to hold that legal determinations are reviewed under a de novo standard. Second, we also hold that the clear error standard of review is appropriate in FOIA cases where a party challenges the underlying facts that support the trial court's decision. In that case, the appellate court must defer to the trial court's view of the facts unless the appellate court is left with the definite and firm conviction that a mistake has been made by the trial court. Finally, when an appellate court reviews a decision committed to the trial court's discretion . . . we hold that the appellate court must review the discretionary determination for an abuse of discretion and cannot disturb the trial court's decision unless it falls outside the principled range of outcomes.

Id. at 471-72.