Hi Stuart,

If I say:
If Len(Dir(Application.Path & "\" & "abc.exe")) _
= 0 Then
Exit Sub
Else
etc
End If

Can I reliably assume that Exit Sub will only occur if the file 'abc.exe' is
not found in the Office-installed path?

Yep (in the path of the Excel.exe file).

Regards

Stephen Bullen
Microsoft MVP - Excel

Professional Excel Development
The most advanced Excel VBA book available
www.oaltd.co.uk/ProExcelDev