Minn. Stat. § 181.041: GARNISHMENT; ASSIGNMENT, SALE, OR TRANSFER OF WAGES; WHEN NOT EFFECTIVE.

No assignment, sale, or transfer, however made or attempted, of any earned or unearned wages or salary is in any manner valid or effectual for the transfer of any salary or wages and should be disregarded if made following service of a garnishment exemption notice and within ten days prior to the receipt of the first garnishment or execution on a debt.