diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs b/src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs
index 3c605a4..538fc01 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs
@@ -524,6 +524,14 @@ namespace Cysharp.Threading.Tasks
             {
                 sb.AppendFormat("------{0}------", header.type.Name);
                 sb.AppendLine();
+                
+                if (header.subSystemList is null) 
+                {
+                    sb.AppendFormat("{0} has no subsystems!", header.ToString());
+                    sb.AppendLine();
+                    continue;
+                }
+
                 foreach (var subSystem in header.subSystemList)
                 {
                     sb.AppendFormat("{0}", subSystem.type.Name);
@@ -545,6 +553,11 @@ namespace Cysharp.Threading.Tasks
 
             foreach (var header in playerLoop.subSystemList)
             {
+                if (header.subSystemList is null) 
+                { 
+                    continue;
+                }
+                
                 foreach (var subSystem in header.subSystemList)
                 {
                     if (subSystem.type == typeof(UniTaskLoopRunners.UniTaskLoopRunnerInitialization))