Not a mistake of Microsoft

Some info abt creating files or folders.......


The following reserved device names cannot be used as the name of a file:

CON, PRN, AUX, CLOCK$, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8,
COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9.

Those names are reserved cause they are 'DOS' device names.

DOS device names are reserved words, and cannot be used as folder or file
names. When parsing a reference to a file or folder, Windows correctly
checks for the case in which a single DOS device name is used in the path,
and treats it as invalid.