VBA functions that wrap GetShortPathName/GetLongPathName of Win32API.

VBAShortPathLongPathConversion.bas

#If VBA7 Then
Private Declare PtrSafe Function Win32APIGetShortPathName Lib "kernel32" Alias "GetShortPathNameA" _
  (ByVal lpszLongPath As String, ByVal lpszShortPath As String, ByVal cchBuffer As LongLong) As LongLong
#Else
Private Declare Function Win32APIGetShortPathName Lib "kernel32" Alias "GetShortPathNameA" _
  (ByVal lpszLongPath As String, ByVal lpszShortPath As String, ByVal cchBuffer As LongLong) As Long
#End If

#If VBA7 Then
Private Declare PtrSafe Function Win32APIGetLongPathName Lib "kernel32" Alias "GetLongPathNameA" _
  (ByVal lpszShortPath As String, ByVal lpszLongPath As String, ByVal cchBuffer As LongLong) As LongLong
#Else
Private Declare Function Win32APIGetLongPathName Lib "kernel32" Alias "GetLongPathNameA" _
  (ByVal lpszShortPath As String, ByVal lpszLongPath As String, ByVal cchBuffer As Long) As Long
#End If

Function GetShortPathName(ByVal longPath As String) As String
    Const PATH_LENGTH = 260

    Dim pathBuffer As String
    pathBuffer = String$(PATH_LENGTH + 1, vbNull)

    #If VBA7 Then
    Dim pathLength As LongLong
    #Else
    Dim pathLength As Long
    #End If
    pathLength = Win32APIGetShortPathName(longPath, pathBuffer, PATH_LENGTH)
    
    GetShortPathName = Left(pathBuffer, CLng(pathLength))
End Function

Function GetLongPathName(ByVal shortPath As String) As String
    Const PATH_LENGTH = 260

    Dim pathBuffer As String
    pathBuffer = String$(PATH_LENGTH + 1, vbNull)

    #If VBA7 Then
    Dim pathLength As LongLong
    #Else
    Dim pathLength As Long
    #End If
    pathLength = Win32APIGetLongPathName(shortPath, pathBuffer, PATH_LENGTH)
    
    GetLongPathName = Left(pathBuffer, CLng(pathLength))

End Function