File Saved as CON, AUX, or PRN Hangs Excel

SUMMARY

If you try to save a file as "CON", "AUX", or "PRN" with any extension from Excel for Windows version 2.10d or earlier, the system hangs. These are reserved filenames in DOS; therefore, they cannot be used as filenames in applications.

In Excel for Windows version 3.00, attempting to save a file as "CON", or "AUX" will produce the message, "Filename is not Valid". Attempting to save a file as "PRN" will produce the message, "Cannot Access 'PRN.XLS'.

The following are possible error messages in other Windows applications such as Word for Windows, Notepad, Paintbrush, Write, etc., where <ext> is the extension appropriate for that application:

1. Replace existing CON.<ext>?

2. Overwrite existing CON.<ext>?

3. Unable to write file to disk; check to determine if the file or disk is damaged.

4. System error. Cannot write to device AUX. Retry, Cancel

5. Cannot write file; check to see if your disk is full.

6. Cannot access document.

MORE INFORMATION

The following was taken from the Microsoft Press book, "The MS-DOS Encyclopedia":

MS-DOS makes input and output device-independent by treating peripheral devices as if they were files. To do this, it assigned a reserved filename to each of the three devices it recognized: CON for the console (keyboard and display), PRN for the printer, and AUX for the auxiliary serial ports. Whenever one of these reserved names appears in the file control block of a file named in a command, all operations are directed to the device rather than to a disk file.