diff --git a/RhSolutions.AddIn/AddIn/RhSolutionsAddIn.cs b/RhSolutions.AddIn/AddIn/RhSolutionsAddIn.cs
index cd62e22..f664491 100644
--- a/RhSolutions.AddIn/AddIn/RhSolutionsAddIn.cs
+++ b/RhSolutions.AddIn/AddIn/RhSolutionsAddIn.cs
@@ -4,7 +4,7 @@ namespace RhSolutions.AddIn;
 
 public sealed class RhSolutionsAddIn : IExcelAddIn
 {
-    public static Application Excel { get; private set; }
+    public static readonly Application Excel = (Application)ExcelDnaUtil.Application;
     public static ServiceProvider ServiceProvider { get; private set; }
     public static IAddInConfiguration Configuration { get; private set; }
 
@@ -14,7 +14,6 @@ public sealed class RhSolutionsAddIn : IExcelAddIn
 
         Services.AddHttpClient()
             .AddMemoryCache()
-            .AddSingleton((Application)ExcelDnaUtil.Application)
             .AddSingleton<IAddInConfiguration, AddInConfiguration>()
             .AddSingleton<IDatabaseClient, DatabaseClient>()
             .AddSingleton<ICurrencyClient, CurrencyClient>()
@@ -44,7 +43,6 @@ public sealed class RhSolutionsAddIn : IExcelAddIn
 
         ServiceProvider = Services.BuildServiceProvider();
         Configuration = ServiceProvider.GetService<IAddInConfiguration>();
-        Excel = ServiceProvider.GetService<Application>();
 
         EventsUtil.Initialize();