diff --git a/launcher/ui/pages/instance/McClient.hpp b/launcher/ui/pages/instance/McClient.hpp
index 992328504..f171ae674 100644
--- a/launcher/ui/pages/instance/McClient.hpp
+++ b/launcher/ui/pages/instance/McClient.hpp
@@ -90,7 +90,7 @@ public:
             );
         }
 
-        int jsonLength = readVarInt(resp);
+        Q_UNUSED(readVarInt(resp)); // json length
         std::string json = resp.toStdString();
 
         QJsonDocument doc = QJsonDocument::fromJson(QByteArray::fromStdString(json));