To list the running instances of Excel:
#If VBA7 Then
Private Declare PtrSafe Function AccessibleObjectFromWindow Lib "oleacc" ( _
ByVal hwnd As LongPtr, ByVal dwId As Long, riid As Any, ppvObject As Object) As Long
Private Declare PtrSafe Function FindWindowExA Lib "user32" ( _
ByVal hwndParent As LongPtr, ByVal hwndChildAfter As LongPtr, _
ByVal lpszClass As String, ByVal lpszWindow As String) As LongPtr
#Else
Private Declare Function AccessibleObjectFromWindow Lib "oleacc" ( _
ByVal hwnd As Long, ByVal dwId As Long, riid As Any, ppvObject As Object) As Long
Private Declare Function FindWindowExA Lib "user32" ( _
ByVal hwndParent As Long, ByVal hwndChildAfter As Long, _
ByVal lpszClass As String, ByVal lpszWindow As String) As Long
#End If
Sub Test()
Dim xl As Application
For Each xl In GetExcelInstances()
Debug.Print "Handle: " & xl.ActiveWorkbook.FullName
Next
End Sub
Public Function GetExcelInstances() As Collection
Dim guid&(0 To 3), acc As Object, hwnd, hwnd2, hwnd3
guid(0) = &H20400
guid(1) = &H0
guid(2) = &HC0
guid(3) = &H46000000
Set GetExcelInstances = New Collection
Do
hwnd = FindWindowExA(0, hwnd, "XLMAIN", vbNullString)
If hwnd = 0 Then Exit Do
hwnd2 = FindWindowExA(hwnd, 0, "XLDESK", vbNullString)
hwnd3 = FindWindowExA(hwnd2, 0, "EXCEL7", vbNullString)
If AccessibleObjectFromWindow(hwnd3, &HFFFFFFF0, guid(0), acc) = 0 Then
GetExcelInstances.Add acc.Application
End If
Loop
End Function