In general With respect to any lost or missing participant of a plan, the plan shall not be treated as failing to satisfy the requirements of this paragraph or any other requirement of this title which cannot be satisfied due to the plan's inability to locate the participant. (ii) Lost or missing participant For purposes of subclause (i), the term lost or missing participant means any employee or the beneficiary of an employee with respect to whom the plan administrator or other responsible party (including a plan service provider or trustee or issuer of an individual retirement plan receiving a transfer described in section 401(a)(31)(B)) has— (I) satisfied the requirements of section 6057(a), (II) made at least one unsuccessful attempt to contact the individual at the most recent address maintained for the individual in the records of the plan, by certified mail or other similar delivery service if the most recent address is a physical address, and by electronic mail or other electronic communication if the only address on record is an electronic address, and (III) has taken at least one (two, in the case of an individual for whom the plan records contain only an electronic address) of the additional measures described in clause (iii) to attempt to locate the individual. (iii) Additional measures The additional measures described in this clause are the following, when taken by a plan administrator or other responsible party: (I) Checked with the administrator of a related plan or checked the plan sponsor’s records for an updated address. (II) Made at least one unsuccessful attempt to contact the individual’s designated plan beneficiary, by the methods described in clause (ii)(II). (III) Performed at least one search using free electronic search tools. (IV) Attempted to locate the participant using a commercial locator service. (iv) Cessation of status An individual shall cease to be treated as a lost or missing participant during any period the plan administrator has actual knowledge of the individual’s