Sub CheckColors()
Dim lr As Long
Dim r As Long
Dim ct As Integer
Dim c As Long
Application.ScreenUpdating = False
' Find last row in column F with data
lr = Cells(Rows.Count, "F").End(xlUp).Row
' Loop through all rows
For r = 1 To lr
' See if columns F, G, and K are all yellow
If (Cells(r, "F").Interior.Color = 65535) And _
(Cells(r, "G").Interior.Color = 65535) And _
(Cells(r, "K").Interior.Color = 65535) Then
' Update column M
Cells(r, "M") = "yellow"
End If
Next r
Application.ScreenUpdating = True
End Sub