copyfile api help.

[DrUnicode]

Path has trailing "\" and "\tmp.txt" has leading "\" so that means there are 2 "\".
Use QualifyPath Function which adds a trailing "\" when necessary.

Option Explicit

Private Declare Function CopyFile Lib "kernel32" Alias "CopyFileA" (ByVal lpExistingFileName As String, ByVal lpNewFileName As String, ByVal bFailIfExists As Long) As Long
Private Sub Form_Load()
   Dim Path             As String
   Dim Path2            As String
   Path = QualifyPath("C:\")
   Path2 = QualifyPath("D:\")
   Dim g
   g = CopyFile(Path & "tmp.txt", Path2 & "temp.txt", True)
   g = CopyFile(Path & "tmp2.txt", Path2 & "temp2.txt", True)
   g = CopyFile(Path & "tmp3.txt", Path2 & "temp3.txt", True)
   g = CopyFile(Path & "tmp4.txt", Path2 & "temp4.txt", True)
   g = CopyFile(Path & "tmp5.txt", Path2 & "temp5.txt", True)
   g = CopyFile(Path & "tmp6.txt", Path2 & "temp5.txt", True)
   g = CopyFile(Path & "tmp7.txt", Path2 & "temp6.txt", True)
End Sub

Public Function QualifyPath(ByVal Path As String) As String
   Dim Delimiter        As String   ' segmented path delimiter

   If InStr(Path, "://") > 0 Then      ' it's a URL path
      Delimiter = "/"                 ' use URL path delimiter
   Else                                ' it's a disk based path
      Delimiter = "\"                 ' use disk based path delimiter
   End If

   Select Case Right$(Path, 1)         ' whats last character in path?
      Case "/", "\"                       ' it's one of the valid delimiters
         QualifyPath = Path              ' use the supplied path
      Case Else                           ' needs a trailing path delimiter
         QualifyPath = Path & Delimiter  ' append it
   End Select
End Function