Is it failing when the filename or its path contains blank spaces in them?
Try this...

Shell Environ("comspec") & " /c """ & ProgramFile & _
""" <""" & InFile & _
""" """ & OutFile & """", vbNormalFocus

Rick


"Daniel" wrote in message
...
I have been using the shell command often this way:

Shell Environ("comspec") & " /c " & ProgramFile & " <" & InFile & " " &
OutFile, vbNormalFocus

Sometimes it works and sometimes it does not (within the same directory,
the
path is OK.) It does not seem to be reading the input file of the
executable.

any ideas?

Thanks
Dan