Sub to remove duplicate IDs and combine multiple lookup results into single cells

hi there. do upload an excel sample so that we do not have to manually key in your data to do a testing.

try this code here:

Sub test()

LR = Cells(Rows.Count, 1).End(xlUp).Row

With Sheets("Desired Output")
    .Cells(1, 1).Resize(LR, 2) = Cells(1, 1).Resize(LR, 2).Value
    For RowX = LR To 2 Step -1
        If .Cells(RowX, 1) = .Cells(RowX - 1, 1) Then
            .Cells(RowX - 1, "B") = .Cells(RowX - 1, "B") & "," & .Cells(RowX, "B")
            .Rows(RowX).Delete
        End If
    Next
    .Activate
End With

MsgBox "Done!"

End Sub

How to install your new code

1. Copy the Excel VBA code
2. Select the workbook in which you want to store the Excel VBA code
3. Press Alt+F11 to open the Visual Basic Editor
4. Choose Insert > Module
5. Edit > Paste the macro into the module that appeared
6. Close the VBEditor
7. Save your workbook (Excel 2007+ select a macro-enabled file format, like *.xlsm)

To run the Excel VBA code:

1. Press Alt-F8 to open the macro list
2. Select a macro in the list
3. Click the Run button