diff --git a/indra/newview/viewer_manifest.py b/indra/newview/viewer_manifest.py
index 66ebd607c47915b0a1dc5abc0c5d71543593eeae..024f2f655cf3244a23d6df7d38219fb48c7d38f6 100755
--- a/indra/newview/viewer_manifest.py
+++ b/indra/newview/viewer_manifest.py
@@ -398,6 +398,8 @@ def package_finish(self):
         sign_py = os.path.expandvars("${SIGN}")
         if not sign_py or sign_py == "${SIGN}":
             sign_py = 'C:\\buildscripts\\code-signing\\sign.py'
+        else:
+            sign_py = sign_py.replace('\\', '\\\\')
         python = os.path.expandvars("${PYTHON}")
         if not python or python == "${PYTHON}":
             python = 'python'