diff --git a/src/TileSource.js b/src/TileSource.js
index 2ae3f63..a247bf5 100644
--- a/src/TileSource.js
+++ b/src/TileSource.js
@@ -168,7 +168,8 @@ class TileSource {
       fs.mkdirSync(path);
       return true;
     } catch (error) {
-      return error.code === 'EEXIST';
+      if (error.code === 'EEXIST') return true;
+      throw error;
     }
   }
 }