diff --git a/win/tools/autopatch/autopatch.py b/win/tools/autopatch/autopatch.py
index 99074ad..996f3d3 100755
--- a/win/tools/autopatch/autopatch.py
+++ b/win/tools/autopatch/autopatch.py
@@ -54,6 +54,9 @@ class ExtractException(Exception):
 class PatternNotFoundException(Exception):
     pass
 
+class UnknownPlatformException(Exception):
+    pass
+
 
 class ExtractedTarget:
     name = None
@@ -173,8 +176,11 @@ def main():
             os_prefix = 'ws2012_x64'
         elif 'winserv-2016' in installer_name:
             os_prefix = 'ws2016_x64'
-        else:
+        elif 'win10' in installer_name:
             os_prefix = 'win10_x64'
+        else:
+            raise UnknownPlatformException("Can't infer platform from filename %s"
+                                           % (repr(installer_name),))
         driver_name = drv_prefix[product_type] + version
         out_dir = os.path.join(
             os.path.dirname(