Try something like this -

Private Declare Function ShellExecute Lib "shell32.dll" _
Alias "ShellExecuteA" (ByVal hwnd As Long, _
ByVal lpOperation As String, _
ByVal lpFile As String, _
ByVal lpParameters As String, _
ByVal lpDirectory As String, _
ByVal nShowCmd As Long) As Long

Private Declare Function GetDesktopWindow Lib "user32" () As Long

Sub test()
Dim ret As Long
Dim sFile As String

sFile = "C:\Temp\test.txt"

ret = ShellExecute(GetDesktopWindow, vbNullString, sFile, _
vbNullString, vbNullString, vbNormalFocus)

If ret 32 Then
' it worked
Else
' it failed, the code 1-32 will give the reason, eg
' 2 file not found
' 31 file not associated
Debug.Print ret
End If

End Sub

If it doesn't work and you are sure the extention is correctly associated
and sure the file is correct, try changing the first vbNullString to "open"
(with the quotes)

Regards,
Peter T


"MikeZz" wrote in message
...
Hi,
I have a file with a ".mac" extention that's associated with an
application
in windows.

Is there a way that I can have Excel run the file from within VBA?

Thanks
MikeZz