Why some File-Names are not allowed in Windows?

Do You Know?

You cannot name “CON” for any folder or a file in Windows operating system. I tried it in my Windows 7 and the following message displayed:

File named CONYou can also try it. A email forward said that the cause behind this is unknown and even Microsoft Team cannot explain why this might be so.  But this is totally untrue.

According to Hoax-Slayer The “team” at Microsoft, and a great many others besides, know perfectly well why you cannot name a folder “CON”. “CON” and a number of other character strings are in fact reserved names that go back to the days of DOS and cannot be used to name folders or files. Other reserved names are:

  • PRN
  • AUX
  • NUL
  • LPT1
  • COM1
  • Potential drive letter – A: to Z:
  • A number of others

If you try to name a folder using one of these reserved names, the name will automatically revert to the default, generally “New Folder”. Moreover, if you try to use a reserved name to name a file such as a Notepad or Microsoft Word document you will generally receive an error message saying, “This file name is a reserved device name. Please choose another name and try again.”

Depending on exactly how you save the file, you may instead receive a warning message advising that a file with that name already exists. However, even if you choose “Yes” to overwrite the existing file, you will still not be allowed to save the file.

It should be noted that, by entering the right sequence of commands via the command prompt, it is usually possible to circumvent the restriction in Winodows and create a folder using a reserved name. However, this may cause other problems and is not advisable, especially for more inexperienced users.

You may also like:

Leave a Comment