per ovviare al tuo problema usa i nomi dei file dos

codice:
Private Declare Function GetShortPathName Lib "kernel32" Alias "GetShortPathNameA" _
(ByVal lpszLongPath As String, ByVal lpszShortPath As String, _
 ByVal lBuffer As Long) As Long
Public Function GetShortPath(strFileName As String) As String

    Dim lngRes As Long
    Dim strPath As String
    
    strPath = Space$(255)
    lngRes = GetShortPathName(strFileName, strPath, 255)

    GetShortPath = trim$(strPath)
End Function