diff --git a/appveyor.yml b/appveyor.yml
index e6647f4..998abca 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -6,8 +6,7 @@ environment:
     - nodejs_version: 4
 
 cache:
-  directories:
-    - node_modules
+  - "node_modules"
 
 # Enable when https://github.com/yarnpkg/yarn/issues/1233 and
 # https://github.com/yarnpkg/yarn/issues/1059 are resolved and disable npm cache