diff --git a/builders/windows-builder.py b/builders/windows-builder.py
index 88ae839..7ebb43c 100644
--- a/builders/windows-builder.py
+++ b/builders/windows-builder.py
@@ -112,6 +112,7 @@ import os
 import glob
 import sys
 from distutils import dir_util
+from hashlib import md5
 from shutil import copy, move, rmtree
 
 from lxml.etree import fromstring, tostring
@@ -171,7 +172,7 @@ class WindowsBuilder(Builder):
                 if fname in BLACKLIST:
                     continue
                 source = os.path.join(path, fname) if path else fname
-                source_id = source.replace('-', '_').replace(os.sep, '_')
+                source_id = md5(source).hexdigest()
                 file_id = 'file_{source_id}'.format(source_id=source_id)
                 component_id = 'cmp_{source_id}'.format(source_id=source_id)
                 file_ = E.File(Id=file_id, KeyPath="yes", Source=source)