List folders in directory, with update function - vba

Question

Im trying to get a list of all folders in a directory. and have a button that enables an update, on the list, without re-creating it every time. So only listing new folder that are not already in the excel sheet.
This is the code that I have working. But I would like it to be able to search the sheet if the folder is already there, if it is then skip it, if not the add it. Once the update it completed the filter by name in column C
Sub folder_names_including_subfolder()
Application.ScreenUpdating = False
Dim fldpath
Dim fso As Object, j As Long, folder1 As Object
If ActiveSheet.Name = "test" Then
fldpath = "Z:\\"
ElseIf ActiveSheet.Name = "test1" Then
fldpath = "Y:\\"
End If
Cells(3, 1).Value = fldpath
Cells(4, 1).Value = "Path"
Cells(4, 2).Value = "Dir"
Cells(4, 3).Value = "Name"
Cells(4, 4).Value = "Folder Size"
Cells(4, 5).Value = "Date Created"
Cells(4, 6).Value = "Date Last Modified"
Cells(4, 7).Value = "Codec"
Set fso = CreateObject("Scripting.FileSystemObject")
Set folder1 = fso.GetFolder(fldpath)
get_sub_folder folder1
Set fso = Nothing
Range("A3").Font.Size = 9
ActiveWindow.DisplayGridlines = False
Range("A3:G" & Range("A4").End(xlDown).Row).Font.Size = 9
Range("A4:G4").Interior.Color = vbCyan
Application.ScreenUpdating = True
End Sub
Sub get_sub_folder(ByRef prntfld As Object)
Dim SubFolder As Object, subfld As Object, j As Long
For Each SubFolder In prntfld.SubFolders
j = Range("A3").End(xlDown).Row + 1
Cells(j, 1).Value = SubFolder.Path
Cells(j, 2).Value = Left(SubFolder.Path, InStrRev(SubFolder.Path, "\"))
Cells(j, 3).Value = SubFolder.Name
Cells(j, 4).Value = Application.WorksheetFunction.RoundDown((((SubFolder.Size / 1024) / 1024) / 1024), 2) & " " & "GB"
Cells(j, 5).Value = SubFolder.DateCreated
Cells(j, 6).Value = SubFolder.DateLastModified
With Cells(j, 7).Validation
.Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:= _
xlBetween, Formula1:="=Sheet3!$A$1:$A$5"
.IgnoreBlank = True
.InCellDropdown = True
.InputTitle = ""
.ErrorTitle = ""
.InputMessage = ""
.ErrorMessage = ""
.ShowInput = True
.ShowError = True
End With
Next SubFolder
For Each subfld In prntfld.SubFolders
get_sub_folder subfld
Next subfld
Columns("C:F").AutoFit
Columns("G").ColumnWidth = 10
End Sub

Answer 1

Just test before storing the material:
For Each SubFolder In prntfld.SubFolders
checkit = SubFolder.Name
If Application.WorksheetFunction.CountIf(Range("C:C"), checkit) = 0 Then
j = Range("A3").End(xlDown).Row + 1
Cells(j, 1).Value = SubFolder.Path
Cells(j, 2).Value = Left(SubFolder.Path, InStrRev(SubFolder.Path, "\"))
Cells(j, 3).Value = SubFolder.Name
Cells(j, 4).Value = Application.WorksheetFunction.RoundDown((((SubFolder.Size / 1024) / 1024) / 1024), 2) & " " & "GB"
Cells(j, 5).Value = SubFolder.DateCreated
Cells(j, 6).Value = SubFolder.DateLastModified
With Cells(j, 7).Validation
.Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:= _
xlBetween, Formula1:="=Sheet3!$A$1:$A$5"
.IgnoreBlank = True
.InCellDropdown = True
.InputTitle = ""
.ErrorTitle = ""
.InputMessage = ""
.ErrorMessage = ""
.ShowInput = True
.ShowError = True
End With
End If
Next SubFolder