S.D. Codified Laws § 21-48-26
All mortgage foreclosure sales of real property by advertisement under power of sale contained in such mortgages, in which the sheriff's certificate of sale therefor was executed and recorded before January 1, 1992, in the office of the register of deeds of the county, or counties, where the real estate affected thereby is situated, are, notwithstanding any defect or irregularity therein, hereby cured, legalized, and validated.
The provisions of this section do not apply to any action or proceeding involving real property pending on July 1, 1993, or commenced prior to July 1, 1993, if a notice of the pendency of such action or proceeding was recorded prior to July 1, 1993.
If anyone has any right in any real property, or any part thereof, adversely affected by a mortgage foreclosure sale referred to in this section, and no action or proceeding to enforce such right is commenced prior to July 1, 1993, such right shall be forever barred, and no action or proceeding so brought may be of any force or effect, or maintainable in any court of this state, unless prior to July 1, 1993, a notice of the pendency of such action or proceeding was recorded in accordance with the provisions of chapter 15-10 in the office of the register of deeds of the county, or counties, where any real property affected thereby is situated.
SDCL 21-48-26