Why can't you use special characters in a filename, like "?" or ";"?

Question

When I try to save a file, if I use special characters in the name (such as a colon, question mark, or exclamation point) in Windows I get a message saying that the file name is invalid.

Why is that?

Answer 1

There are several characters that have special meaning to Windows (and to DOS, where most of the characters originally came from)

from MSDN:

A filename cannot contain any of the following characters:
\ / : * ? " < > |

/ is a switch (and also a directory separator).
\ is a directory separator.
: is a drive designator.
* and ? are wildcards used in searching.
" is a way to allow spaces in parameters.
< and > are redirection that allow input and output of a program to come from, and go to, something other than screen/keyboard.
| is a pipe that allows output from one program to be used as input to the next.