diff --git a/appveyor.yml b/appveyor.yml
index 289302112..2f94ab328 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -29,7 +29,7 @@ install:
     $ProgressPreference = 'SilentlyContinue'
 
 
-    git submodule sync
+    git submodule sync --recursive
 
 
     if ($LastExitCode -ne 0) {