My son earned an income in Ohio, but lives in Michigan. Does he have to file a return for Ohio?

Since MI and OH have reciprocal agreements, you only need to file a MI return.

No.

In the personal info section, when it asks if you made money in another state, answer NO, per the reciprocal state instructions, on that page. This will prevent TurboTax from thinking you need to file an OH return.

However the reciprocity agreement does not apply to local city taxes. You are not required to file an Ohio local city return, but you are also not entitled to a refund of the city withholding (box19 on your W-2), unless there was an error in the amount.

Michigan will give you credit, on the MI state return for OH city tax withheld, but you have to attach a copy of the city return. So, even though the Ohio city does not require you to file a return, you have to file one to get the MI credit, even though there will be no tax due or refunded from the Ohio city.