Abstract: Advantage is taken in the fact that the files that operate beyond a single application, for example, (executable files) are files having extensions which are already known to the system and which extensions must be appended to a file name in the last position of the file name. In one embodiment, when a file is incoming to a computer system the executable nature of the file is temporarily inhibited by modifying the last extension. This modification can be by appending a new “safe” extension to the end of the file name, which appended extension must be removed before the file will execute. The safe extension could, if desired, convey information to the user about the nature of the file. In one embodiment, files containing potentially troubling data are identified to the user. In another embodiment, the user must acknowledge his/her desire to open an executable file.