diff --git a/.appveyor.yml b/.appveyor.yml
index 065ca87..1227a93 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -3,6 +3,7 @@ os:
 - Visual Studio 2017
 
 build_script:
+  - git submodule update --init --recursive
   - mkdir build
   - cd build
   - cmake ..