--- a/testing/talos/talos/cmanager_win32.py
+++ b/testing/talos/talos/cmanager_win32.py
@@ -33,23 +33,23 @@ def _getExpandedCounterPaths(processName
     '''
     pcchPathListLength = DWORD(0)
     szWildCardPath = LPSTR('\\process(%s)\\%s' % (processName, counterName))
     if pdh.PdhExpandCounterPathA(
         szWildCardPath,
         LPSTR(None),
         pointer(pcchPathListLength)
     ) != _PDH_MORE_DATA:
-        return None
+        return []
 
     pathListLength = pcchPathListLength.value
     szExpandedPathList = LPCSTR('\0' * pathListLength)
     if pdh.PdhExpandCounterPathA(szWildCardPath, szExpandedPathList,
                                  pointer(pcchPathListLength)) != 0:
-        return None
+        return []
     buffer = create_string_buffer(pcchPathListLength.value)
     memmove(buffer, szExpandedPathList, pcchPathListLength.value)
 
     paths = []
     i = 0
     path = ''
     for j in range(0, pcchPathListLength.value):
         c = struct.unpack_from('c', buffer, offset=j)[0]