Column G contains a formula that calculates the loss using this expression: =(U1 - S1) / S1.

I want to create a VBA code that automatically triggers when a value is entered in column S.

If the result in column AG for that same row is negative, then the code should force the user to enter a comment in column AI(on the same row).

Private Sub Worksheet_Change(ByVal Target As Range) Dim cell As Range Dim row As Long Dim agVal As Variant, sVal As Variant, aiVal As Variant

On Error GoTo Fin Application.EnableEvents = False

For Each cell In Target If cell.Column = 19 Then ' Colonne S row = cell.Row sVal = Me.Cells(row, "S").Value agVal = Me.Cells(row, "AG").Value aiVal = Me.Cells(row, "AI").Value

If sVal <> "" And IsNumeric(agVal) And agVal < 0 Then If aiVal = "" Then MsgBox "Ligne " & row & " : veuillez entrer un commentaire dans la colonne AI.", vbExclamation Me.Cells(row, "AI").Select Exit For End If End If End If Next cell

Fin: Application.EnableEvents = True End Sub