>I did not know that. I used this code with an old app that ran on a win95 box. So, if NUL is not a valid device in NT, do you know what will work to check for the existence of a diskette in drive A?
>

You can use Scripting.FileSystemObject; the following works without requiring an API call that will alter the reporting of system errors by WinNT or Win2K:

oFSO=CREATEOBJ('Scripting.FileSystemObject')
? oFSO.Drives.Item('A:').IsReady

If you use any of the native VFP mechanisms like DISKSPACE() to test, NT and Win2K will cause an error dialog to appear unless you alter the OS handling of errors with SetErrorMode()