Hi

try this. adjust the sheet names in the code.

Code:
Option Explicit

Sub kTest()
    
    Dim ka, k(), i As Long, n As Long, c As Long, d As Object
    
    Const MasterSheet   As String = "Sheet1"    '<< adjust
    Const NewData       As String = "Sheet2"    '<< adjust
    
    Set d = CreateObject("scripting.dictionary")
        d.comparemode = 1
    
    ka = ThisWorkbook.Worksheets(MasterSheet).Range("a1").CurrentRegion.Resize(, 10).Value2
    
    For i = 2 To UBound(ka, 1)
        If Len(Trim(ka(i, 4))) Then
            d.Item(Trim(ka(i, 4))) = Empty
        End If
    Next
    
    Erase ka
    ka = ThisWorkbook.Worksheets(NewData).Range("a1").CurrentRegion.Resize(, 10).Value2
    ReDim k(1 To UBound(ka, 1), 1 To UBound(ka, 2))
    
    For i = 2 To UBound(ka, 1)
        If Not d.exists(ka(i, 4)) Then
            n = n + 1
            For c = 1 To UBound(ka, 2)
                k(n, c) = ka(i, c)
            Next
        End If
    Next
    
    If n Then
        'append new record into the master sheet
        With ThisWorkbook.Worksheets(MasterSheet)
            .Range("a" & .Rows.Count).End(xlUp).Offset(1).Resize(n, UBound(k, 2)) = k
        End With
    End If
    
End Sub