Perform macro based on cell value

Hi all, I have a macro in place but it is very sluggish.

When i exit a specific sheet (Sheet 3), I would like the values in columns K,L and M to be fixed if the corrosponding row value in column H is "Y".

I have the below code but as mentioned it is very time consuming and freezes the screen when running. if there is a better way please could someone assist?

Private Sub Worksheet_Deactivate()
Application.ScreenUpdating = False

 Sheet3.Unprotect 
Dim lRow As Long, lCounter As Long
 lRow = Cells(Rows.Count, 1).End(xlUp).Row
 For lCounter = 2 To lRow
    If Cells(lCounter, 8) = "Y" Then
        With Cells(lCounter, 11).Resize(1, 3)
        .Value = .Value
            End With
        
    End If
 Next lCounter
 Sheet3.Protect DrawingObjects:=True, Contents:=True, Scenarios:=True _
        , AllowFiltering:=True, 
 Application.ScreenUpdating = True
End Sub

Try this:

Private Sub Worksheet_Deactivate()
Application.ScreenUpdating = False

Dim iRow as Range
Dim FirstMatch

 Sheet3.Unprotect 

  Set iRow=Column(8).Find("Y", Lookat:=xlWhole)
  If Not iRow is Nothing Then
     FirstMatch=iRow.Address
     While Not iRow Is Nothing
        iRow.Resize(1, 3)
       Set iRow=Column(8).FindNext(iRow)
       If iRow.Address=FirstMatch Then Set iRow=Nothing
     Wend
   End If

 Sheet3.Protect DrawingObjects:=True, Contents:=True, Scenarios:=True _
        , AllowFiltering:=True, 
 Application.ScreenUpdating = True
End Sub

Hi, I get an error on the iRow.Resize(1, 3) saying an = is required

Hi Domski - that worked perfectly. Thank you