Concon

is a computer bug that appeared in the Windows 95 and Windows 98 operating systems. The name comes from the fact that referring to the file "C:\con\con" would crash these systems. This was a particular case of a more general bug, where the system failed to respond correctly to file paths containing multiple device file names. (In the example, "con" is the device file name for the console device.) Such file paths are invalid on Windows, because device file names are reserved words. Even though the system would report an error if "C:\con" were accessed, the system would miss the attempted reference to "con" in the case of accessing "C:\con\con".