diff --git a/lib/mbtiles.js b/lib/mbtiles.js
index d6cf95e..f194451 100644
--- a/lib/mbtiles.js
+++ b/lib/mbtiles.js
@@ -61,7 +61,7 @@ function MBTiles(uri, callback) {
     var mbtiles = cache[key];
     if (!mbtiles.open && !mbtiles.error) {
         mbtiles.once('open', function(err, mbtiles) {
-            delete cache[key];
+            if (err) delete cache[key];
             callback(err, mbtiles);
         });
     } else {