Sub concatemails()
Dim plg As Range, lignes As Long, i As Long, j As Long, m$
Set plg = _
Range(Cells(1, 1), Cells(65536, 1).End(xlUp))
lignes = plg.Rows.Count
j = 1
For i = 1 To lignes
If i = lignes Then
m = m & Cells(i, 1).Text
Else
m = m & Cells(i, 1).Text & Chr(59)
If InStr(m, Chr(59)) > 0 Then j = j + 1
End If
Next
Cells(1, 5) = m
If j > 30 Then
If (MsgBox("Trente emails déjà concaténés!", vbCritical + vbOKOnly, "Avertissement") = vbOK) Then Cells(1, 5).ClearContents
End If
Set plg = Nothing
End Sub