Windows Explorer is the default graphical file system browser and manager included in all Microsoft operating systems since Windows 95. It is sometimes referred to as the "Windows Shell," though it is actually just one component of the Windows shell.
It was first included as a replacement for the Windows 3.1 "File Manager" and has changed and been upgraded substantially since its first release, though is still essentially the same program. As such, it retains some limitations from as far back as Windows 95, such as not being able to work on paths with more than 260 characters.
In Windows 8 and Server 2012, it has been renamed to " File Explorer," had its UI changed substantially, and includes some new features, most notably, the ability to pause and resume File System operations.