A method and system for ensuring scanning of suspicious computer files without unnecessary caching of the files on a network device is provided. A network device receives a suspicious computer file and determines whether a target computer is protected by a malware protection program. If the network device determines that the target computer is protected by the malware protection program, the network device modifies the suspicious computer file to make the suspicious computer file unusable by the target computer and sends the modified suspicious computer file to the target computer.