Minn. Stat. § 281.324: CANCELED BY LIMITATION.

The county auditor shall annually, as soon as practicable after the second Monday of May, cancel of record all real estate tax judgment sale certificates, forfeited tax sale certificates, and state assignment certificates, upon which notice of expiration of the time of redemption has not been served, and recorded or filed of record within the time herein fixed, by making any entry "canceled by limitation" in the proper real estate tax judgment book opposite the description of land covered by such certificate.