diff --git a/src/pmtiles_adapter.js b/src/pmtiles_adapter.js
index 192732c..f71c931 100644
--- a/src/pmtiles_adapter.js
+++ b/src/pmtiles_adapter.js
@@ -154,6 +154,7 @@ const ReadBytes = async (filePath, offset, size) => {
       break;
     }
   }
+  fs.closeSync(fd); //close file when finished
 
   return BufferToArrayBuffer(sharedBuffer);
 };