By default, Windows 8.1's file manager, the File Explorer application (formerly known as Windows Explorer) does not show the file extension for most file types. This is a security risk as anyone could send you a malicious file named "Runme.txt.exe" but Windows will hide the .exe portion, so an inexperienced user can inadvertently open the file thinking that it is a text file and malware will infect his or her PC.
In this article we will look how to change this behavior so file extensions are always shown, and, as a bonus, we will also look at how we can force File Explorer to always show or always hide file extensions for a specific file type.
