I want to automatically update cell comments with time stamp last time cell changed

Hi, Med_MV,

add a loop to work on each cell which has been modified:

Private Sub Worksheet_Change(ByVal Target As Range)
Dim rngCell As Range
For Each rngCell In Target
    With rngCell
        .ClearComments
        .AddComment ("Last Modified " & Date)
        .Comment.Visible = False
    End With
Next rngCell
End Sub

Ciao,
Holger