Public Sub List(frm As Form, Ctrl As Control, i As Long)

    Dim rs As DAO.Recordset
    Dim Str As String
    Dim strSQL As String
     
    Set rs = frm.RecordsetClone
    Str =  "" "  - третья кавычка отсутствует :)
    If rs.RecordCount <>  0  Then
        rs.MoveFirst
        Do Until rs.EOF
            Str = Str & rs.Fields(i).Value &  "; " 
            rs.MoveNext
        Loop
            Ctrl.RowSource = Str
        rs.Close
    End If

End Sub

Public Sub List(frm As Form, Ctrl As Control, i As Long)

    Dim rs As DAO.Recordset
    Dim StrArr, StrRow, ArrRow
    Dim x As Integer

    Set StrArr = CreateObject( "Scripting.Dictionary" )
    Set rs = frm.RecordsetClone
    StrArr.removeall
    StrRow =  ""
    ArrRow = "  "
    x = 1 

    rs.MoveFirst
        Do Until rs.EOF
            x = x +  1 
            StrArr.Add x, rs.Fields(i).Value & "; "
            rs.MoveNext
        Loop
        
        ArrRow = StrArr.items
        For x =  0  To StrArr.Count -  1 
             StrRow = StrRow & ArrRow(x)
        Next
        Debug.Print StrRow
End Sub

Public Sub List(frm As Form, Ctrl As Control, i As Long)

    Dim rs As DAO.Recordset
    Dim StrArr, StrRow, ArrRow
    Dim X As Integer
    
    Set StrArr = CreateObject( "Scripting.Dictionary" )
    Set rs = frm.RecordsetClone
    StrArr.removeall
    StrRow =  ""
    ArrRow = "  " " 
    X =  0 

    rs.MoveFirst
        Do Until rs.EOF
            X = X +  1 
            StrArr.Add X, rs.Fields(i).Value &  "; " 
            rs.MoveNext
        Loop
        
        ArrRow = StrArr.Items

        rs.MoveFirst
        For X =  0  To StrArr.Count -  1  And rs.EOF
            If rs.Fields(i).Value &  "; "  = ArrRow(X) Then
                rs.MoveNext
            Else
                StrRow = StrRow & ArrRow(X)
                rs.MoveNext
            End If
        Next X
            
Debug.Print StrRow
End Sub