diff --git a/lib/cache.js b/lib/cache.js
index 20be221e1..8ed6a0d7a 100644
--- a/lib/cache.js
+++ b/lib/cache.js
@@ -39,8 +39,11 @@ var Cache = Object.derive(function(path, dir) {
       deps: this.deps,
       info: info
     };
-    fis.util.write(this.cacheInfo, JSON.stringify(infos));
-    fis.util.write(this.cacheFile, content);
+
+    if (content) {
+      fis.util.write(this.cacheInfo, JSON.stringify(infos));
+      fis.util.write(this.cacheFile, content);
+    }
   },
 
   /**