diff --git a/src/Ryujinx.HLE/Debugger/Debugger.cs b/src/Ryujinx.HLE/Debugger/Debugger.cs
index d7521b17b..e9f535440 100644
--- a/src/Ryujinx.HLE/Debugger/Debugger.cs
+++ b/src/Ryujinx.HLE/Debugger/Debugger.cs
@@ -554,11 +554,17 @@ namespace Ryujinx.HLE.Debugger
 
         void CommandSetThread(char op, ulong? threadId)
         {
-            if (threadId == 0)
+            if (threadId == 0 || threadId == null)
             {
                 threadId = GetThreads().First().ThreadUid;
             }
 
+            if (DebugProcess.GetThread(threadId.Value) == null)
+            {
+                ReplyError();
+                return;
+            }
+
             switch (op)
             {
                 case 'c':
diff --git a/src/Ryujinx.HLE/HOS/Kernel/Process/KProcess.cs b/src/Ryujinx.HLE/HOS/Kernel/Process/KProcess.cs
index 0dd280489..abd792cc5 100644
--- a/src/Ryujinx.HLE/HOS/Kernel/Process/KProcess.cs
+++ b/src/Ryujinx.HLE/HOS/Kernel/Process/KProcess.cs
@@ -1306,7 +1306,8 @@ namespace Ryujinx.HLE.HOS.Kernel.Process
             {
                 lock (_parent._threadingLock)
                 {
-                    return _parent._threads.Select(x => x.ThreadUid).ToArray();
+                    var threads = _parent._threads.Where(x => !x.TerminationRequested).ToArray();
+                    return threads.Select(x => x.ThreadUid).ToArray();
                 }
             }
 
@@ -1314,7 +1315,8 @@ namespace Ryujinx.HLE.HOS.Kernel.Process
             {
                 lock (_parent._threadingLock)
                 {
-                    return _parent._threads.FirstOrDefault(x => x.ThreadUid == threadUid);
+                    var threads = _parent._threads.Where(x => !x.TerminationRequested).ToArray();
+                    return threads.FirstOrDefault(x => x.ThreadUid == threadUid);
                 }
             }