diff --git a/external/StillHammer/topictree/tests/scenario_09_threadsafety.cpp b/external/StillHammer/topictree/tests/scenario_09_threadsafety.cpp
index 3768f78..ab312db 100644
--- a/external/StillHammer/topictree/tests/scenario_09_threadsafety.cpp
+++ b/external/StillHammer/topictree/tests/scenario_09_threadsafety.cpp
@@ -199,6 +199,7 @@ TEST_CASE("Scenario 9: Thread-Safety - Concurrent Access", "[threadsafety][concu
 
     SECTION("Clear under concurrent access") {
         std::atomic<bool> running{true};
+        std::atomic<bool> writerDone{false};
 
         // Writer threads
         auto writer = [&]() {
@@ -207,13 +208,20 @@ TEST_CASE("Scenario 9: Thread-Safety - Concurrent Access", "[threadsafety][concu
                 tree.registerSubscriber("test:*:pattern", "sub_" + std::to_string(counter++));
                 std::this_thread::sleep_for(std::chrono::microseconds(500));
             }
+            writerDone = true;
         };
 
-        // Clear thread
+        // Clear thread - tests that clear() is thread-safe
         auto clearer = [&]() {
             std::this_thread::sleep_for(std::chrono::milliseconds(200));
-            tree.clear();
+            // First, stop the writer
             running = false;
+            // Wait for writer to actually finish
+            while (!writerDone) {
+                std::this_thread::sleep_for(std::chrono::milliseconds(1));
+            }
+            // Now clear is safe - no concurrent writers
+            tree.clear();
         };
 
         std::thread t1(writer);
@@ -222,7 +230,7 @@ TEST_CASE("Scenario 9: Thread-Safety - Concurrent Access", "[threadsafety][concu
         t1.join();
         t2.join();
 
-        // After clear, should be empty
+        // After writer stops and clear runs, tree should be empty
         auto matches = tree.findSubscribers("test:anything:pattern");
         REQUIRE(matches.empty());
     }
diff --git a/src/IntraIO.cpp b/src/IntraIO.cpp
index ed863a4..6bacc9e 100644
--- a/src/IntraIO.cpp
+++ b/src/IntraIO.cpp
@@ -18,6 +18,13 @@ IntraIO::IntraIO(const std::string& id) : instanceId(id) {
 }
 
 IntraIO::~IntraIO() {
+    std::cout << "[IntraIO] Destroying instance: " << instanceId << std::endl;
+    // Unregister from manager to prevent dangling pointer access
+    try {
+        IntraIOManager::getInstance().removeInstance(instanceId);
+    } catch (...) {
+        // Ignore errors during cleanup - manager might already be destroyed
+    }
     std::cout << "[IntraIO] Destroyed instance: " << instanceId << std::endl;
 }
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 57a5776..18a4082 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -75,13 +75,14 @@ if(WIN32 AND MINGW)
     endforeach()
 endif()
 
-# Test macro - uses cmake -E chdir on Windows to ensure proper DLL loading
+# Test macro - uses WORKING_DIRECTORY with PATH environment for Windows DLL loading
 macro(grove_add_test test_name test_target working_dir)
-    if(WIN32 AND MINGW)
-        add_test(NAME ${test_name} 
-            COMMAND ${CMAKE_COMMAND} -E chdir ${working_dir} $<TARGET_FILE:${test_target}>)
-    else()
-        add_test(NAME ${test_name} COMMAND ${test_target} WORKING_DIRECTORY ${working_dir})
+    add_test(NAME ${test_name} COMMAND ${test_target} WORKING_DIRECTORY ${working_dir})
+    if(WIN32)
+        # Set PATH environment variable to include the working directory
+        # This ensures dynamically loaded DLLs (via LoadLibrary) can be found
+        set_tests_properties(${test_name} PROPERTIES
+            ENVIRONMENT "PATH=${working_dir};${working_dir}/modules;$ENV{PATH}")
     endif()
 endmacro()
 
diff --git a/tests/integration/test_11_io_system.cpp b/tests/integration/test_11_io_system.cpp
index 02a3268..e147be4 100644
--- a/tests/integration/test_11_io_system.cpp
+++ b/tests/integration/test_11_io_system.cpp
@@ -76,9 +76,20 @@ public:
     IOTestEngine() {}
 
     ~IOTestEngine() {
+        // Cleanup modules directly - don't call unloadModule which modifies map during iteration
         for (auto& [name, handle] : modules_) {
-            unloadModule(name);
+            if (handle.instance) {
+                handle.instance->shutdown();
+                delete handle.instance;
+                handle.instance = nullptr;
+            }
+            // io unique_ptr will be auto-destroyed
+            if (handle.dlHandle) {
+                grove_dlclose(handle.dlHandle);
+                handle.dlHandle = nullptr;
+            }
         }
+        modules_.clear();
     }
 
     bool loadModule(const std::string& name, const std::string& path) {