S.C. Code Ann. § 15-3-380: Effect of forty-year lapse.

No action shall be commenced in any case for the recovery of real property or for any interest therein against a person in possession under claim of title by virtue of a written instrument unless the person claiming, his ancestor or grantor, was actually in the possession of the same or a part thereof within forty years from the commencement of such action. And the possession of a defendant, sole or connected, pursuant to the provisions of this section shall be deemed valid against the world after the lapse of such a period.