Beispiel:

Option Explicit
 
Public Declare Function DeleteFile Lib _
    "kernel32" Alias _
    "DeleteFileA" _
    (ByVal lpFileName As String) _
    As Long
 
Public Function IsDriveWritable( _
                sDrive As String) _
                As Boolean
  '// -----------------------------------------------------
  '// Methode:   | Prüft ob Laufwerk beschreibbar ist
  '// -----------------------------------------------------
  '// Parameter: | sDrive = Laufwerksbuchstaben
  '//            |          (Beispiel: E:\)
  '// -----------------------------------------------------
  '// Rückgabe:  | True = Laufwerk ist beschreibbar;
  '//            | False = Laufwerk ist nicht beschreibbar
  '// -----------------------------------------------------
  '// Autor:     | Stefan Kulpa
  '//            | EDV Innovation & Consulting - Dormagen
  '// -----------------------------------------------------
  Dim iFile As Integer
  Dim sFile As String
 
  On Error GoTo Err_IsDriveWritable
  sFile = VBA.Left$(sDrive, 1) + ":TEST.$$$"
  iFile = FreeFile
  Open sFile For Random As #iFile Len = 1
  Close #iFile
  IsDriveWritable = (Err.Number = 0)
  DeleteFile sFile
 
Exit_IsDriveWritable:
  On Error GoTo 0
  Exit Function
 
Err_IsDriveWritable:
  IsDriveWritable = (Err.Number = 0)
  Resume Exit_IsDriveWritable
 
End Function