diff --git a/src/Avalonia.Base/Styling/Activators/StyleActivatorBase.cs b/src/Avalonia.Base/Styling/Activators/StyleActivatorBase.cs
index a4639b8feb..412151b92f 100644
--- a/src/Avalonia.Base/Styling/Activators/StyleActivatorBase.cs
+++ b/src/Avalonia.Base/Styling/Activators/StyleActivatorBase.cs
@@ -29,6 +29,9 @@ namespace Avalonia.Styling.Activators
 
         public void Unsubscribe(IStyleActivatorSink sink)
         {
+            if (_sink is null)
+                return;
+
             if (_sink != sink)
             {
                 throw new AvaloniaInternalException("StyleActivatorSink is not subscribed.");