excel vba macro to match cells from two different workbooks and copy and paste accordingly

Question

i have 2 workbooks, workbook A and workbook B. Each workbook has a table. workbook A has 2 columns. All three columns are filled.

1. product_id
2. Machine_

Answer 1

try this

Sub UpdateW2()
    Dim Dic As Object, key As Variant, oCell As Range, i&
    Dim w1 As Worksheet, w2 As Worksheet

    Set Dic = CreateObject("Scripting.Dictionary")
    Set w1 = Workbooks("workbookA.xlsm").Sheets("Sheet1")
    Set w2 = Workbooks("workbookB.xlsm").Sheets("Sheet1")

    i = w1.Cells.SpecialCells(xlCellTypeLastCell).Row

    For Each oCell In w1.Range("D2:D" & i)
        If Not Dic.exists(oCell.Value) Then
            Dic.Add oCell.Value, oCell.Offset(, -3).Value
        End If
    Next

    i = w2.Cells.SpecialCells(xlCellTypeLastCell).Row

    For Each oCell In w2.Range("A2:A" & i)
        For Each key In Dic
            If oCell.Value = key Then
                oCell.Offset(, 2).Value = Dic(key)
            End If
        Next
    Next
End Sub

UPDATE AGAINST NEW REQUIREMENTS

use this

Sub UpdateW2()
    Dim key As Variant, oCell As Range, i&, z%
    Dim w1 As Worksheet, w2 As Worksheet
    Dim Dic As Object: Set Dic = CreateObject("Scripting.Dictionary")
    Dim Dic2 As Object: Set Dic2 = CreateObject("Scripting.Dictionary")
    Set w1 = Workbooks("workbookA.xlsm").Sheets("Sheet1")
    Set w2 = Workbooks("workbookB.xlsm").Sheets("Sheet1")
    '-------------------------------------------------------------------------
    'get the last row for w1
    i = w1.Cells.SpecialCells(xlCellTypeLastCell).Row
    '-------------------------------------------------------------------------
    ' fill dictionary with data for searching
    For Each oCell In w1.Range("D2:D" & i)
        'row number for duplicates
        z = 1: While Dic.exists(oCell.Value & "_" & z): z = z + 1: Wend
        'add data with row number to dictionary
        If Not Dic.exists(oCell.Value & "_" & z) Then
            Dic.Add oCell.Value & "_" & z, oCell.Offset(, -3).Value
        End If
    Next
    '-------------------------------------------------------------------------
    'get the last row for w2
    i = w2.Cells.SpecialCells(xlCellTypeLastCell).Row
    '-------------------------------------------------------------------------
    'fill "B" with results
    For Each oCell In w2.Range("A2:A" & i)
        'determinate row number for duplicated values
        z = 1: While Dic2.exists(oCell.Value & "_" & z): z = z + 1: Wend
        'search
        For Each key In Dic
            If oCell.Value & "_" & z = key Then
                oCell.Offset(, 2).Value = Dic(key)
            End If
        Next
        'correction of the dictionary in case
        'when sheet "A" has less duplicates than sheet "B"
        If oCell.Offset(, 2).Value = "" Then
            Dic2.RemoveAll: z = 1
            For Each key In Dic
                If oCell.Value & "_" & z = key Then
                    oCell.Offset(, 2).Value = Dic(key)
                End If
            Next
        End If
        'add to dictionary already passed results for
        'the next duplicates testing
        If Not Dic2.exists(oCell.Value & "_" & z) Then
            Dic2.Add oCell.Value & "_" & z, ""
        End If
    Next
End Sub

output results below

Answer 2

I tried to replicate your workbooks, I believe they go something like this

Before After

Code changes are minor,

Sub UpdateW2()

    Dim w1 As Worksheet, w2 As Worksheet
    Dim c As Range, FR As Long

    Application.ScreenUpdating = False

    Set w1 = Workbooks("BookOne.xlsm").Worksheets("Sheet1")
    Set w2 = Workbooks("BookTwo.xlsm").Worksheets("Sheet1")


    For Each c In w1.Range("D2", w1.Range("D" & Rows.Count).End(xlUp))
        FR = 0
        On Error Resume Next
        FR = Application.Match(c, w2.Columns("A"), 0)
        On Error GoTo 0
        If FR <> 0 Then w2.Range("C" & FR).Value = c.Offset(, -3)
    Next c
    Application.ScreenUpdating = True
End Sub