diff --git a/src/R3.Blazor/ObservableSystemInitializationService.cs b/src/R3.Blazor/ObservableSystemInitializationService.cs
index 77fd1014..67c834b5 100644
--- a/src/R3.Blazor/ObservableSystemInitializationService.cs
+++ b/src/R3.Blazor/ObservableSystemInitializationService.cs
@@ -1,15 +1,17 @@
-namespace R3;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+
+namespace R3;
 
 public static class BlazorR3Extensions
 {
     public static IServiceCollection AddBlazorR3(this IServiceCollection services)
     {
-        return AddBlazorR3(services, _ => new SynchronizationContextTimeProvider(), null!);
+        return AddBlazorR3(services, _ => new SynchronizationContextTimeProvider(() => SynchronizationContext.Current), null!);
     }
 
     public static IServiceCollection AddBlazorR3(this IServiceCollection services, Action<Exception> unhandledExceptionHandler)
     {
-        return AddBlazorR3(services, _ => new SynchronizationContextTimeProvider(), unhandledExceptionHandler);
+        return AddBlazorR3(services, _ => new SynchronizationContextTimeProvider(() => SynchronizationContext.Current), unhandledExceptionHandler);
     }
 
     public static IServiceCollection AddBlazorR3(this IServiceCollection services, Func<IServiceProvider, TimeProvider> timeProviderFactory)
@@ -20,7 +22,7 @@ public static IServiceCollection AddBlazorR3(this IServiceCollection services, F
     public static IServiceCollection AddBlazorR3(this IServiceCollection services, Func<IServiceProvider, TimeProvider> timeProviderFactory, Action<Exception> unhandledExceptionHandler)
     {
         services.AddHttpContextAccessor();
-        services.AddScoped<TimeProvider>(timeProviderFactory);
+        services.TryAddSingleton<TimeProvider>(timeProviderFactory);
         services.AddHostedService(sp => new ObservableSystemInitializationService(sp.GetRequiredService<IHttpContextAccessor>(), unhandledExceptionHandler));
 
         return services;
diff --git a/src/R3/SynchronizationContextTimeProvider.cs b/src/R3/SynchronizationContextTimeProvider.cs
index 373dae49..762589db 100644
--- a/src/R3/SynchronizationContextTimeProvider.cs
+++ b/src/R3/SynchronizationContextTimeProvider.cs
@@ -2,7 +2,7 @@
 
 public sealed class SynchronizationContextTimeProvider : TimeProvider
 {
-    readonly SynchronizationContext? synchronizationContext;
+    readonly Func<SynchronizationContext?> synchronizationContextAccessor;
     readonly TimeProvider timeProvider;
 
     public SynchronizationContextTimeProvider()
@@ -15,15 +15,26 @@ public SynchronizationContextTimeProvider(SynchronizationContext? synchronizatio
     {
     }
 
+    public SynchronizationContextTimeProvider(Func<SynchronizationContext?> synchronizationContextAccessor)
+        : this(synchronizationContextAccessor, TimeProvider.System)
+    {
+    }
+
     public SynchronizationContextTimeProvider(SynchronizationContext? synchronizationContext, TimeProvider timeProvider)
     {
-        this.synchronizationContext = synchronizationContext;
+        this.synchronizationContextAccessor = () => synchronizationContext;
+        this.timeProvider = timeProvider;
+    }
+
+    public SynchronizationContextTimeProvider(Func<SynchronizationContext?> synchronizationContextAccessor, TimeProvider timeProvider)
+    {
+        this.synchronizationContextAccessor = synchronizationContextAccessor;
         this.timeProvider = timeProvider;
     }
 
     public override ITimer CreateTimer(TimerCallback callback, object? state, TimeSpan dueTime, TimeSpan period)
     {
-        return new SynchronizationContextTimer(timeProvider, synchronizationContext, callback, state, dueTime, period);
+        return new SynchronizationContextTimer(timeProvider, synchronizationContextAccessor(), callback, state, dueTime, period);
     }
 }