diff --git a/Directory.Build.targets b/Directory.Build.targets
index 28cb1afb..b543c1bc 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -123,6 +123,7 @@
 
   <PropertyGroup
     Condition=" '$(TargetFrameworkIdentifier)' == '.NETCoreApp' And $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '10.0')) ">
+    <DefineConstants>$(DefineConstants);SUPPORTS_ASYNC_LINQ</DefineConstants>
     <DefineConstants>$(DefineConstants);SUPPORTS_RELAXED_URI_LIMITS</DefineConstants>
   </PropertyGroup>
 
diff --git a/sandbox/OpenIddict.Sandbox.AspNetCore.Server/Helpers/AsyncEnumerableExtensions.cs b/sandbox/OpenIddict.Sandbox.AspNetCore.Server/Helpers/AsyncEnumerableExtensions.cs
index 946d35e7..01adf0ee 100644
--- a/sandbox/OpenIddict.Sandbox.AspNetCore.Server/Helpers/AsyncEnumerableExtensions.cs
+++ b/sandbox/OpenIddict.Sandbox.AspNetCore.Server/Helpers/AsyncEnumerableExtensions.cs
@@ -1,4 +1,5 @@
-namespace OpenIddict.Sandbox.AspNetCore.Server.Helpers;
+#if !SUPPORTS_ASYNC_LINQ
+namespace OpenIddict.Sandbox.AspNetCore.Server.Helpers;
 
 public static class AsyncEnumerableExtensions
 {
@@ -24,3 +25,4 @@ public static class AsyncEnumerableExtensions
         }
     }
 }
+#endif