Try this out.....

If you try MKDIR CON in the command window, you get the message 'The directory name is invalid'.

It is a reserved word, old baggage from the days of MS-DOS. The same applies to a number of other words like AUX, COM1-4, LPT1-3, NUL, PRN.

yes reserved . but
con = console ......
you can't make a directory named con .

maybe the reason is that the abbreviation Con is close to convict? I dunno.

Be honest, how many of us went right away and tried to name a folder con?

I looked briefly through the registry to see if I could spot a way to allow these and other reserved words to be used. If there is, I didn't find it.

here is why http://www.microsoft.com/technet/treeview/...kc_fil_rbrx.asp

File names in Windows XP Professional can be up to 255 characters and can contain spaces, multiple periods, and special characters that are not allowed in MS-DOS file names. Windows XP Professional makes it possible for other operating systems to access files that have long names by generating an MS-DOS-readable (8.3) name for each file. These MS-DOS-readable names also enable MS-DOS-based and Windows 3.x?based applications to recognize and load files that have long file names. When a program saves a file on a computer running Windows XP Professional, both the 8.3 file name and long file name are retained.

Note

The 8.3 format means that files can have between 1 and 8 characters in the file name. The name must start with a letter or a number and can contain any characters except the following:
. " / \ [ ] : ; | = , * ? (space)
An 8.3 file name typically has a file name extension that is from one to three characters long and has the same character restrictions. A period separates the file name from the file name extension.
Several special file names are reserved by the system and cannot be used for files or folders:
CON, AUX, COM1, COM2, COM3, COM4, LPT1, LPT2, LPT3, PRN, NUL