The findValue parameter for the X509Certificate2Collection.Find(X509FindType, object, bool) method must be a DateTime value in local time. The value does not have to be in the future. For example, you can use X509FindType.FindByTimeNotYetValid to find certificates that became valid in the current year by taking the intersection of the results of a X509Certificate2Collection.Find(X509FindType, object, bool) operation for X509FindType.FindByTimeNotYetValid for the last day of last year with the results of a X509Certificate2Collection.Find(X509FindType, object, bool) operation for X509FindType.FindByTimeValid of DateTime.Now.