When the deed of trust with the release thereon is filed for the purpose of recording the release, the clerk shall retain such deed of trust in his office and not permit the same to be again withdrawn; provided, however, that if the release is partial in its character after the recording of same, the clerk may permit the deed of trust to be withdrawn. (Mont. Co. Code 1965, § 8-5; 1927, ch. 493, § 187.)