Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

■ More than one condition can cause this error:
 
  • A statement or command references a file with a number or
    name that is not specified in the OPEN statement, or that
    is out of the range of file numbers specified earlier in
    the program.
 
  • An OPEN statement references a negative file number, file
    number 0, or has a file number assigned with an
    uninitialized variable.
 
  • No ISAM table (or any other file) is currently open with
    the file number used in an ISAM statement or function.
 
  • A file exists with the file name used in an ISAM OPEN FOR
    statement, but it was not created by ISAM.
 
  • You have used an invalid file name in an ISAM OPEN FOR
    statement. A file name must conform to the MS-DOS naming
    conventions.
 
■ If you need additional help, move the cursor to a keyword
  and press F1 to open the Help window.