Error msg "Not enough system resources"

hello

I have this error msg

"Not enough system resources to display completely"

here

Private Sub cmCode_Change() 'Material code
For i = 3 To Sheets("Lists").ES
        If Me.cmCode.Text = Sheets("Lists").Cells(i, "S").Text Then
            Me.txtName.Text = Sheets("Lists").Cells(i, "T").Text
            Exit For
        End If
    Next
End Sub

How can i avoid that again ?