diff --git a/src/modules/launcher/Wox/ViewModel/MainViewModel.cs b/src/modules/launcher/Wox/ViewModel/MainViewModel.cs
index 11ebfa5f1a..2706eda0b8 100644
--- a/src/modules/launcher/Wox/ViewModel/MainViewModel.cs
+++ b/src/modules/launcher/Wox/ViewModel/MainViewModel.cs
@@ -222,9 +222,9 @@ namespace Wox.ViewModel
         public ResultsViewModel ContextMenu { get; private set; }
         public ResultsViewModel History { get; private set; }
 
-        public string SystemQueryText { get; set; }
+        public string SystemQueryText { get; set; } = String.Empty;
 
-        public string QueryText { get; set; }
+        public string QueryText { get; set; } = String.Empty;
       
 
         /// <summary>