VBA copyfile it it doesn't exist - vba

Question

I have a list of file in 2 columns A and B.
A column is the source the B
B column is the destination
The code below copy file from source to destination. But if the destination exists it give me errors. What is the condition so that if it find that it exists it will not do anyting ??
What is the wrong with the code ?
Sub FC_Copy()
Dim ClientsFolderDestination
Dim fso As New FileSystemObject
Dim rep_destination
Dim source
lastrow = ThisWorkbook.Worksheets("XClients").Cells(Application.Rows.Count, 1).End(xlUp).Row
For i = 5 To lastrow
source = ThisWorkbook.Worksheets("XClients").Cells(i, 1).Value
ClientsFolderDestination= ThisWorkbook.Worksheets("XClients").Cells(i, 2).Value
If fso.FileExists(source) Then
rep_destination = Left(ClientsFolderDestination, Len(ClientsFolderDestination) - Len(fso.GetFileName(ClientsFolderDestination)) - 1)
If Not fso.FolderExists(rep_destination) Then
sub_rep = Split(rep_destination, "\")
myrep = sub_rep(0)
If Not fso.FolderExists(myrep) Then
MkDir myrep
End If
For irep = 1 To UBound(sub_rep)
myrep = myrep & "\" & sub_rep(irep)
If Not fso.FolderExists(myrep) Then
MkDir myrep
End If
Next
End If
fso.CopyFile source, ClientsFolderDestination
End If
Next i
end sub

Answer 1

Try this.
This doesn't use Microsoft Scripting Runtime Library.
It uses one common function to check for existence of file and folder
It caters for destination paths like C:\Sample.xlsx
Code
Sub FC_Copy()
Dim ws As Worksheet
Dim source As String, Destination As String, sTemp As String
Dim lRow As Long, i As Long, j As Long
Dim MyAr As Variant
Set ws = ThisWorkbook.Sheets("XClients")
With ws
'~~> Find Last Row
lRow = .Range("A" & .Rows.Count).End(xlUp).Row
For i = 5 To lRow
source = .Range("A" & i).Value
Destination = .Range("B" & i).Value
MyAr = Split(Destination, "\")
'~~> This check is required for destination paths like C:\Sample.xlsx
If UBound(MyAr) > 1 Then
sTemp = MyAr(0)
For j = 1 To UBound(MyAr)
sTemp = sTemp & "\" & MyAr(j)
If Not FileFolderExists(sTemp) = True Then MkDir sTemp
Next j
End If
If Not FileFolderExists(Destination) Then FileCopy source, Destination
Next i
End With
End Sub
Public Function FileFolderExists(strFullPath As String) As Boolean
On Error GoTo Whoa
If Not Dir(strFullPath, vbDirectory) = vbNullString Then FileFolderExists = True
On Error GoTo 0
Whoa:
End Function

Answer 2

If Not fso.FileExists(ClientsFolderDestination) Then
fso.CopyFile source, ClientsFolderDestination
End If
or if you want to overwrite the destination file
fso.CopyFile source, ClientsFolderDestination, True
CopyFile Method