diff --git a/include/SparkyStudios/Audio/Amplitude/Core/Memory.h b/include/SparkyStudios/Audio/Amplitude/Core/Memory.h
index 493b938..8dcfcb1 100644
--- a/include/SparkyStudios/Audio/Amplitude/Core/Memory.h
+++ b/include/SparkyStudios/Audio/Amplitude/Core/Memory.h
@@ -325,7 +325,7 @@ namespace SparkyStudios::Audio::Amplitude
      *
      * @ingroup memory
      */
-    class MemoryAllocator
+    class AM_API_PUBLIC MemoryAllocator
     {
     public:
         /**
diff --git a/src/Core/Codec.cpp b/src/Core/Codec.cpp
index 29a11a9..5022d87 100644
--- a/src/Core/Codec.cpp
+++ b/src/Core/Codec.cpp
@@ -78,7 +78,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Codec::Register(Codec* codec)
     {
-        if (lockCodecs())
+        if (lockCodecs() || codec == nullptr)
             return;
 
         if (Find(codec->GetName()) != nullptr)
@@ -94,7 +94,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Codec::Unregister(const Codec* codec)
     {
-        if (lockCodecs())
+        if (lockCodecs() || codec == nullptr)
             return;
 
         CodecRegistry& codecs = codecRegistry();
diff --git a/src/Core/Driver.cpp b/src/Core/Driver.cpp
index 56c2d8a..d202594 100644
--- a/src/Core/Driver.cpp
+++ b/src/Core/Driver.cpp
@@ -64,7 +64,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Driver::Register(Driver* driver)
     {
-        if (lockDrivers())
+        if (lockDrivers() || driver == nullptr)
             return;
 
         if (Find(driver->GetName()) != nullptr)
@@ -80,7 +80,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Driver::Unregister(const Driver* driver)
     {
-        if (lockDrivers())
+        if (lockDrivers() || driver == nullptr)
             return;
 
         DriverRegistry& drivers = driverRegistry();
diff --git a/src/Core/Memory.cpp b/src/Core/Memory.cpp
index 5d3d145..6d5a605 100644
--- a/src/Core/Memory.cpp
+++ b/src/Core/Memory.cpp
@@ -118,7 +118,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void MemoryManager::Initialize(std::unique_ptr<MemoryAllocator> allocator)
     {
-        if (gMemManager == nullptr)
+        if (!IsInitialized())
             gMemManager = new MemoryManager(std::move(allocator));
 
 #if !defined(AM_NO_MEMORY_STATS)
diff --git a/src/DSP/Filter.cpp b/src/DSP/Filter.cpp
index b900a8f..c417e51 100644
--- a/src/DSP/Filter.cpp
+++ b/src/DSP/Filter.cpp
@@ -79,22 +79,22 @@ namespace SparkyStudios::Audio::Amplitude
         return m_name;
     }
 
-    void Filter::Register(Filter* codec)
+    void Filter::Register(Filter* filter)
     {
-        if (lockFilters())
+        if (lockFilters() || filter == nullptr)
             return;
 
-        if (Find(codec->GetName()) != nullptr)
+        if (Find(filter->GetName()) != nullptr)
             return;
 
         FilterRegistry& filters = filterRegistry();
-        filters.insert(FilterImpl(codec->GetName(), codec));
+        filters.insert(FilterImpl(filter->GetName(), filter));
         filtersCount()++;
     }
 
     void Filter::Unregister(const Filter* filter)
     {
-        if (lockFilters())
+        if (lockFilters() || filter == nullptr)
             return;
 
         FilterRegistry& filters = filterRegistry();
diff --git a/src/DSP/Resampler.cpp b/src/DSP/Resampler.cpp
index c3ed260..970675e 100644
--- a/src/DSP/Resampler.cpp
+++ b/src/DSP/Resampler.cpp
@@ -63,7 +63,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Resampler::Register(Resampler* resampler)
     {
-        if (lockResamplers())
+        if (lockResamplers() || resampler == nullptr)
             return;
 
         if (Find(resampler->GetName()) != nullptr)
@@ -79,7 +79,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Resampler::Unregister(const Resampler* resampler)
     {
-        if (lockResamplers())
+        if (lockResamplers() || resampler == nullptr)
             return;
 
         ResamplerRegistry& resamplers = resamplerRegistry();
diff --git a/src/Mixer/Node.cpp b/src/Mixer/Node.cpp
index 25f1cc7..f8263a0 100644
--- a/src/Mixer/Node.cpp
+++ b/src/Mixer/Node.cpp
@@ -290,7 +290,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Node::Register(Node* node)
     {
-        if (lockNodes())
+        if (lockNodes() || node == nullptr)
             return;
 
         if (Find(node->GetName()) != nullptr)
@@ -306,7 +306,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Node::Unregister(const Node* node)
     {
-        if (lockNodes())
+        if (lockNodes() || node == nullptr)
             return;
 
         NodeRegistry& nodes = nodeRegistry();
diff --git a/src/Sound/Fader.cpp b/src/Sound/Fader.cpp
index 25e6b12..fd72056 100644
--- a/src/Sound/Fader.cpp
+++ b/src/Sound/Fader.cpp
@@ -249,7 +249,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Fader::Register(Fader* fader)
     {
-        if (lockFaders())
+        if (lockFaders() || fader == nullptr)
             return;
 
         if (Find(fader->GetName()) != nullptr)
@@ -265,7 +265,7 @@ namespace SparkyStudios::Audio::Amplitude
 
     void Fader::Unregister(const Fader* fader)
     {
-        if (lockFaders())
+        if (lockFaders() || fader == nullptr)
             return;
 
         FaderRegistry& faders = faderRegistry();
diff --git a/tests/main.cpp b/tests/main.cpp
index 97489ae..77661e7 100644
--- a/tests/main.cpp
+++ b/tests/main.cpp
@@ -57,6 +57,7 @@ struct AmTestListener : Catch::EventListenerBase
 
         // Register all the default plugins shipped with the engine
         Engine::RegisterDefaultPlugins();
+        Driver::Unregister(Driver::Find("miniaudio"));
 
         const auto sdkPath = std::filesystem::path(std::getenv("AM_SDK_PATH"));
 
diff --git a/tests/thread.cpp b/tests/thread.cpp
index be45f6d..18944c1 100644
--- a/tests/thread.cpp
+++ b/tests/thread.cpp
@@ -175,7 +175,7 @@ TEST_CASE("Thread Pool Tests", "[thread][amplitude]")
                 auto task = std::make_shared<DummyPoolTask>(threadId);
                 REQUIRE_FALSE(task->IsExecuted());
 
-                bool willExecuteWorkInCallerThread = pool.GetTaskCount() >= AM_MAX_THREAD_POOL_TASKS;
+                bool willExecuteWorkInCallerThread = pool.GetTaskCount() > AM_MAX_THREAD_POOL_TASKS;
 
                 pool.AddTask(task);