VBA code to import data, doing lookups to detect duplicates
This should be twice as fast:

dlr = wb1.Worksheets("INPUT_DATA").Cells(Rows.Count, 1).End(xlUp).Row
wb1.Worksheets("INPUT_DATA").Range("A2:S" &amp; dlr).ClearFormats

'check duplicate values before import to TOTAL_DATA
    Tlr = wb1.Worksheets("TOTAL_DATA").Cells(Rows.Count, 1).End(xlUp).Row
    countMatch = 0
    countUnmatch = 0

For cell = 2 To dlr
    Cells(cell, 20).Formula = "=CONCAT(RC[-19], ""__"",RC[-18])"

    Cells(cell, 21).Formula = "=IF(ISNA(VLOOKUP(RC[-1],TOTAL_DATA!C30,1,FALSE)), ""No"", ""Yes"")"
    If Cells(cell, 21).Value = "Yes" Then
        Cells(cell, 20).Font.Color = vbRed
        countMatch = countMatch + 1
    Else
        Range("A" &amp; cell, "T" &amp; cell).Cut Destination:=wb1.Worksheets("TOTAL_DATA").Range("A" &amp; Tlr + 1)
        Tlr = Tlr + 1
        countUnmatch = countUnmatch + 1
    End If
Next cell


Because in here we loop only once from 2 to dlr.