diff --git a/server/core/ZipReader.js b/server/core/ZipReader.js
index 4103cb3..5b9a128 100644
--- a/server/core/ZipReader.js
+++ b/server/core/ZipReader.js
@@ -12,7 +12,7 @@ class ZipReader {
 
     async open(zipFile) {
         if (this.zip)
-            throw new Error('Zip file already open');
+            throw new Error('Zip file is already open');
 
          const zip = new StreamZip.async({file: zipFile});