S.D. Codified Laws § 21-48-22
All proceedings of mortgage foreclosure sale of real property by advertisement, and completed by issuance of sheriff's deed prior to July 1, 1941, and which proceedings were irregular or defective, are hereby legalized, cured and validated as fully as if such foreclosure proceedings had been wholly regular and as by law provided.
The provisions of this section shall not apply to any action involving real property which was pending on July 1, 1951, or which was commenced prior to July 1, 1952, as to which a notice of the pendency of such action was recorded prior to July 1, 1952, as provided herein.
If any person has any vested right in any real property, or any part thereof, by reason of any mortgage foreclosure sale such as is referred to herein, if no action or proceeding to enforce such right was begun prior to July 1, 1952, such rights shall be forever barred; and no action or proceeding so brought shall be of any force or effect, or maintainable in any court of this state, unless, prior to July 1, 1952, there was recorded in the office of the register of deeds of the county in which the real estate affected is situated a notice of the pendency of such action, in accordance with the provisions of chapter 15-10.
SDCL 21-48-22