Sub xtest()
Dim i As Long
Dim r As Range
Dim x As Long
Application.ScreenUpdating = False
For i = [M65536].End(xlUp).Row To 1 Step -1
Set r = Range("M" & i)
x = Application.WorksheetFunction.CountBlank(r.Resize(1, 4))
If x = 4 Then
Range("M" & i).EntireRow.Delete
End If
Next i
Application.ScreenUpdating = True
End Sub