diff --git a/src/audioCore/ara/ARAChangeListener.cpp b/src/audioCore/ara/ARAChangeListener.cpp
new file mode 100644
index 0000000..dd8d881
--- /dev/null
+++ b/src/audioCore/ara/ARAChangeListener.cpp
@@ -0,0 +1,9 @@
+#include "ARAChangeListener.h"
+#include "ARAVirtualDocument.h"
+
+ARAChangeListener::ARAChangeListener(ARAVirtualDocument* document)
+	: document(document) {}
+
+void ARAChangeListener::changeListenerCallback(juce::ChangeBroadcaster* source) {
+	this->document->update();
+}
diff --git a/src/audioCore/ara/ARAChangeListener.h b/src/audioCore/ara/ARAChangeListener.h
new file mode 100644
index 0000000..29a97c2
--- /dev/null
+++ b/src/audioCore/ara/ARAChangeListener.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <JuceHeader.h>
+
+class ARAVirtualDocument;
+
+class ARAChangeListener : public juce::ChangeListener {
+public:
+	ARAChangeListener(ARAVirtualDocument* document);
+
+	void changeListenerCallback(juce::ChangeBroadcaster* source) override;
+
+private:
+	ARAVirtualDocument* const document;
+
+	JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(ARAChangeListener)
+};
diff --git a/src/audioCore/misc/ARAController.cpp b/src/audioCore/ara/ARAController.cpp
similarity index 100%
rename from src/audioCore/misc/ARAController.cpp
rename to src/audioCore/ara/ARAController.cpp
diff --git a/src/audioCore/misc/ARAController.h b/src/audioCore/ara/ARAController.h
similarity index 100%
rename from src/audioCore/misc/ARAController.h
rename to src/audioCore/ara/ARAController.h
diff --git a/src/audioCore/misc/ARAObjects.cpp b/src/audioCore/ara/ARAObjects.cpp
similarity index 100%
rename from src/audioCore/misc/ARAObjects.cpp
rename to src/audioCore/ara/ARAObjects.cpp
diff --git a/src/audioCore/misc/ARAObjects.h b/src/audioCore/ara/ARAObjects.h
similarity index 100%
rename from src/audioCore/misc/ARAObjects.h
rename to src/audioCore/ara/ARAObjects.h
diff --git a/src/audioCore/misc/ARASharedObject.h b/src/audioCore/ara/ARASharedObject.h
similarity index 100%
rename from src/audioCore/misc/ARASharedObject.h
rename to src/audioCore/ara/ARASharedObject.h
diff --git a/src/audioCore/misc/ARAVirtualDocument.cpp b/src/audioCore/ara/ARAVirtualDocument.cpp
similarity index 79%
rename from src/audioCore/misc/ARAVirtualDocument.cpp
rename to src/audioCore/ara/ARAVirtualDocument.cpp
index 574e039..ef507e3 100644
--- a/src/audioCore/misc/ARAVirtualDocument.cpp
+++ b/src/audioCore/ara/ARAVirtualDocument.cpp
@@ -7,15 +7,20 @@ ARAVirtualDocument::ARAVirtualDocument(
 	juce::ARAHostModel::PlaybackRendererInterface& araPlaybackRenderer,
 	const PluginOnOffFunc& pluginOnOff)
 	: seq(seq), controller(controller), pluginOnOff(pluginOnOff),
-	araEditorRenderer(araEditorRenderer), araPlaybackRenderer(araPlaybackRenderer) {}
+	araEditorRenderer(araEditorRenderer), araPlaybackRenderer(araPlaybackRenderer) {
+	this->listener = std::make_unique<ARAChangeListener>(this);
+}
 
 ARAVirtualDocument::~ARAVirtualDocument() {
 	this->clear();
 }
 
 void ARAVirtualDocument::update() {
+	/** Invoke This On Message Thread */
+	JUCE_ASSERT_MESSAGE_THREAD
+
 	/** Turn Off Plugin */
-	this->pluginOnOff(false);
+	this->lockPlugin(true);
 
 	/** Lock Document */
 	juce::ARAEditGuard locker(this->controller);
@@ -47,12 +52,12 @@ void ARAVirtualDocument::update() {
 	this->addRegionToRenderer();
 
 	/** Turn On Plugin */
-	this->pluginOnOff(true);
+	this->lockPlugin(false);
 }
 
 void ARAVirtualDocument::clear() {
 	/** Turn Off Plugin */
-	this->pluginOnOff(false);
+	this->lockPlugin(true);
 
 	/** Lock Document */
 	juce::ARAEditGuard locker(this->controller);
@@ -61,7 +66,11 @@ void ARAVirtualDocument::clear() {
 	this->clearUnsafe();
 
 	/** Turn On Plugin */
-	this->pluginOnOff(true);
+	this->lockPlugin(false);
+}
+
+juce::ChangeListener* ARAVirtualDocument::getListener() const {
+	return this->listener.get();
 }
 
 void ARAVirtualDocument::clearUnsafe() {
@@ -97,3 +106,20 @@ void ARAVirtualDocument::addRegionToRenderer() {
 		}
 	}
 }
+
+void ARAVirtualDocument::lockPlugin(bool locked) {
+	juce::GenericScopedLock locker(this->pluginLockMutex);
+
+	if (locked) {
+		if (this->pluginLockCount == 0) {
+			this->pluginOnOff(false);
+		}
+		this->pluginLockCount++;
+	}
+	else {
+		this->pluginLockCount--;
+		if (this->pluginLockCount == 0) {
+			this->pluginOnOff(true);
+		}
+	}
+}
diff --git a/src/audioCore/misc/ARAVirtualDocument.h b/src/audioCore/ara/ARAVirtualDocument.h
similarity index 85%
rename from src/audioCore/misc/ARAVirtualDocument.h
rename to src/audioCore/ara/ARAVirtualDocument.h
index 7e72c84..847b8a8 100644
--- a/src/audioCore/misc/ARAVirtualDocument.h
+++ b/src/audioCore/ara/ARAVirtualDocument.h
@@ -2,6 +2,7 @@
 
 #include <JuceHeader.h>
 #include "ARAObjects.h"
+#include "ARAChangeListener.h"
 
 class SeqSourceProcessor;
 
@@ -20,12 +21,16 @@ class ARAVirtualDocument {
 	void update();
 	void clear();
 
+	juce::ChangeListener* getListener() const;
+
 private:
 	SeqSourceProcessor* const seq = nullptr;
 	ARA::Host::DocumentController& controller;
 	juce::ARAHostModel::EditorRendererInterface& araEditorRenderer;
 	juce::ARAHostModel::PlaybackRendererInterface& araPlaybackRenderer;
 	const PluginOnOffFunc pluginOnOff;
+	int pluginLockCount = 0;
+	juce::SpinLock pluginLockMutex;
 
 	std::unique_ptr<ARAVirtualAudioSource> audioSource = nullptr;
 	std::unique_ptr<ARAVirtualAudioModification> audioModification = nullptr;
@@ -33,9 +38,13 @@ class ARAVirtualDocument {
 	std::unique_ptr<ARAVirtualRegionSequence> regionSequence = nullptr;
 	std::unique_ptr<ARAVirtualPlaybackRegion> playbackRegion = nullptr;
 
+	std::unique_ptr<ARAChangeListener> listener = nullptr;
+
 	void clearUnsafe();
 	void removeRegionToRenderer();
 	void addRegionToRenderer();
 
+	void lockPlugin(bool locked);
+
 	JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(ARAVirtualDocument)
 };
diff --git a/src/audioCore/graph/PluginDecorator.cpp b/src/audioCore/graph/PluginDecorator.cpp
index 1ceb279..4ab5b09 100644
--- a/src/audioCore/graph/PluginDecorator.cpp
+++ b/src/audioCore/graph/PluginDecorator.cpp
@@ -4,7 +4,7 @@
 #include "../uiCallback/UICallback.h"
 #include "../misc/AudioLock.h"
 #include "../misc/VMath.h"
-#include "../misc/ARAController.h"
+#include "../ara/ARAController.h"
 #include "../AudioCore.h"
 #include "../Utils.h"
 #include <VSP4.h>
@@ -25,6 +25,9 @@ PluginDecorator::PluginDecorator(SeqSourceProcessor* seq,
 	for (int i = 0; i < this->paramCCList.size(); i++) {
 		this->paramCCList[i] = -1;
 	}
+
+	/** ARA Change Broadcaster */
+	this->araChangeBroadcaster = std::make_unique<juce::ChangeBroadcaster>();
 }
 
 PluginDecorator::PluginDecorator(std::unique_ptr<juce::AudioPluginInstance> plugin,
@@ -95,8 +98,8 @@ void PluginDecorator::setPlugin(
 	else {
 		this->plugin->setPlayHead(this->getPlayHead());
 		this->plugin->setNonRealtime(this->isNonRealtime());
-		this->plugin->prepareToPlay(this->getSampleRate(), this->getBlockSize());
-		this->pluginPrepared = true;
+		this->pluginOnOffInternal(true,
+			this->getSampleRate(), this->getBlockSize());
 
 		//this->updatePluginBuses();
 
@@ -137,15 +140,8 @@ void PluginDecorator::setARA(
 				this->araPlaybackRenderer = pluginInstance.getPlaybackRendererInterface();
 
 				/** Plugin On Off */
-				auto pluginOnOffFunc = [plugin = this->plugin.get()](bool on) {
-					if (plugin) {
-						if (on) {
-							plugin->prepareToPlay(plugin->getSampleRate(), plugin->getBlockSize());
-						}
-						else {
-							plugin->releaseResources();
-						}
-					}
+				auto pluginOnOffFunc = [this](bool on) {
+					this->pluginOnOffInternal(on, this->getSampleRate(), this->getBlockSize());
 					};
 
 				/** Create ARA Virtual Document */
@@ -158,14 +154,18 @@ void PluginDecorator::setARA(
 		/** Prepare Plugin */
 		this->plugin->setPlayHead(this->getPlayHead());
 		this->plugin->setNonRealtime(this->isNonRealtime());
-		this->plugin->prepareToPlay(this->getSampleRate(), this->getBlockSize());
-		this->pluginPrepared = true;
+		this->pluginOnOffInternal(true,
+			this->getSampleRate(), this->getBlockSize());
 
 		//this->updatePluginBuses();
 
 		/** Prepare ARA Document */
-		if (this->araDocumentController) {
+		if (this->araVirtualDocument) {
 			this->araVirtualDocument->update();
+
+			/** Add Change Listener */
+			this->araChangeBroadcaster->addChangeListener(
+				this->araVirtualDocument->getListener());
 		}
 
 		/** Callback */
@@ -183,8 +183,8 @@ void PluginDecorator::handleARALoadError(const juce::String& pluginIdentifier) {
 		/** Prepare Plugin */
 		this->plugin->setPlayHead(this->getPlayHead());
 		this->plugin->setNonRealtime(this->isNonRealtime());
-		this->plugin->prepareToPlay(this->getSampleRate(), this->getBlockSize());
-		this->pluginPrepared = true;
+		this->pluginOnOffInternal(true,
+			this->getSampleRate(), this->getBlockSize());
 
 		//this->updatePluginBuses();
 
@@ -395,6 +395,41 @@ void PluginDecorator::clearMIDICCListener() {
 	this->ccListener = MIDICCListener{};
 }
 
+void PluginDecorator::invokeARADocumentChange() {
+	/**
+	 * TODO Make the Celemony Melodyne happy.
+	 * Celemony Melodyne GUI make the host crashed when ARA host document changed.
+	 * Solve this later.
+	 */
+
+	this->pluginOnOffInternal(false,
+		this->getSampleRate(), this->getBlockSize());
+
+	this->araChangeBroadcaster->sendSynchronousChangeMessage();
+	//if (this->araDocumentController) {
+	//	/** Plugin On Off */
+	//	auto pluginOnOffFunc = [this](bool on) {
+	//		this->pluginOnOffInternal(on, this->getSampleRate(), this->getBlockSize());
+	//		};
+
+	//	/** Create ARA Virtual Document */
+	//	this->araVirtualDocument = std::make_unique<ARAVirtualDocument>(
+	//		this->seq, this->araDocumentController->getDocumentController(),
+	//		this->araEditorRenderer, this->araPlaybackRenderer, pluginOnOffFunc);
+
+	//	if (this->araVirtualDocument) {
+	//		this->araVirtualDocument->update();
+
+	//		/** Add Change Listener */
+	//		this->araChangeBroadcaster->addChangeListener(
+	//			this->araVirtualDocument->getListener());
+	//	}
+	//}
+
+	this->pluginOnOffInternal(true,
+		this->getSampleRate(), this->getBlockSize());
+}
+
 const juce::String PluginDecorator::getName() const {
 	if (!this->plugin) { return ""; }
 	return this->plugin->getName() + ((bool)this->araDocumentController ? "(ARA)" : "");
@@ -418,14 +453,15 @@ void PluginDecorator::prepareToPlay(
 		this->doubleBuffer = std::make_unique<juce::AudioBuffer<double>>(channels, this->getBlockSize());
 	}
 
-	this->plugin->prepareToPlay(sampleRate, maximumExpectedSamplesPerBlock);
-	this->pluginPrepared = true;
+	this->pluginOnOffInternal(true,
+		this->getSampleRate(), this->getBlockSize());
 }
 
 void PluginDecorator::releaseResources() {
 	if (!this->plugin) { return; }
-	this->pluginPrepared = false;
-	this->plugin->releaseResources();
+	
+	this->pluginOnOffInternal(false,
+		this->getSampleRate(), this->getBlockSize());
 }
 
 void PluginDecorator::memoryWarningReceived() {
@@ -828,3 +864,36 @@ void PluginDecorator::updateBuffer() {
 		}
 	}
 }
+
+void PluginDecorator::pluginOnOffInternal(bool shouldOn, double sampleRate, int blockSize) {
+	/** Try to fix Celemony Melodyne crash but this not works */
+	/*juce::GenericScopedLock locker(this->pluginOnOffMutex);
+
+	if (shouldOn) {
+		if (this->pluginOnOffCount == 0 && plugin) {
+			plugin->prepareToPlay(sampleRate, blockSize);
+			this->pluginPrepared = true;
+		}
+		this->pluginOnOffCount++;
+	}
+	else {
+		this->pluginOnOffCount--;
+		if (this->pluginOnOffCount == 0 && plugin) {
+			this->pluginPrepared = false;
+			plugin->releaseResources();
+		}
+	}*/
+
+	if (shouldOn) {
+		if (plugin) {
+			plugin->prepareToPlay(sampleRate, blockSize);
+			this->pluginPrepared = true;
+		}
+	}
+	else {
+		if (plugin) {
+			this->pluginPrepared = false;
+			plugin->releaseResources();
+		}
+	}
+}
diff --git a/src/audioCore/graph/PluginDecorator.h b/src/audioCore/graph/PluginDecorator.h
index 1fed318..9c26567 100644
--- a/src/audioCore/graph/PluginDecorator.h
+++ b/src/audioCore/graph/PluginDecorator.h
@@ -2,7 +2,7 @@
 
 #include <JuceHeader.h>
 #include "../project/Serializable.h"
-#include "../misc/ARAVirtualDocument.h"
+#include "../ara/ARAVirtualDocument.h"
 
 class SeqSourceProcessor;
 
@@ -57,6 +57,8 @@ class PluginDecorator final : public juce::AudioProcessor,
 	void setMIDICCListener(const MIDICCListener& listener);
 	void clearMIDICCListener();
 
+	void invokeARADocumentChange();
+
 	class SafePointer {
 	private:
 		juce::WeakReference<PluginDecorator> weakRef;
@@ -163,6 +165,10 @@ class PluginDecorator final : public juce::AudioProcessor,
 	juce::ARAHostModel::EditorRendererInterface araEditorRenderer;
 	juce::ARAHostModel::PlaybackRendererInterface araPlaybackRenderer;
 	std::unique_ptr<ARAVirtualDocument> araVirtualDocument = nullptr;
+	std::unique_ptr<juce::ChangeBroadcaster> araChangeBroadcaster = nullptr;
+
+	int pluginOnOffCount = 0;
+	juce::SpinLock pluginOnOffMutex;
 
 	void numChannelsChanged() override;
 	void numBusesChanged() override;
@@ -175,6 +181,8 @@ class PluginDecorator final : public juce::AudioProcessor,
 	
 	void updateBuffer();
 
+	void pluginOnOffInternal(bool shouldOn, double sampleRate, int blockSize);
+
 	JUCE_DECLARE_WEAK_REFERENCEABLE(PluginDecorator)
 	JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PluginDecorator)
 };
diff --git a/src/audioCore/graph/SeqSourceProcessor.cpp b/src/audioCore/graph/SeqSourceProcessor.cpp
index d76f9c5..5a8128e 100644
--- a/src/audioCore/graph/SeqSourceProcessor.cpp
+++ b/src/audioCore/graph/SeqSourceProcessor.cpp
@@ -99,6 +99,11 @@ int SeqSourceProcessor::resetSeqTime(
 void SeqSourceProcessor::setTrackName(const juce::String& name) {
 	this->trackName = name;
 
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
+
 	/** Callback */
 	UICallbackAPI<int>::invoke(UICallbackType::SeqChanged, this->index);
 }
@@ -110,6 +115,11 @@ const juce::String SeqSourceProcessor::getTrackName() const {
 void SeqSourceProcessor::setTrackColor(const juce::Colour& color) {
 	this->trackColor = color;
 
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
+
 	/** Callback */
 	UICallbackAPI<int>::invoke(UICallbackType::SeqChanged, this->index);
 }
@@ -291,11 +301,22 @@ void SeqSourceProcessor::applyAudio() {
 	/** Callback */
 	auto callback = [ptr = SafePointer{ this }] {
 		if (ptr) {
+			/** ARA Change */
+			if (auto plugin = ptr->getInstrProcessor()) {
+				plugin->invokeARADocumentChange();
+			}
+
+			/** UI Change */
 			ptr->invokeDataCallbacks();
 		}
 		};
 	SourceManager::getInstance()->setCallback(this->audioSourceRef,
 		SourceManager::SourceType::Audio, callback);
+
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
 }
 
 void SeqSourceProcessor::applyMIDI() {
@@ -308,11 +329,22 @@ void SeqSourceProcessor::applyMIDI() {
 	/** Callback */
 	auto callback = [ptr = SafePointer{ this }] {
 		if (ptr) {
+			/** ARA Change */
+			if (auto plugin = ptr->getInstrProcessor()) {
+				plugin->invokeARADocumentChange();
+			}
+
+			/** UI Change */
 			ptr->invokeDataCallbacks();
 		}
 		};
 	SourceManager::getInstance()->setCallback(this->midiSourceRef,
 		SourceManager::SourceType::MIDI, callback);
+
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
 }
 
 void SeqSourceProcessor::releaseAudio() {
@@ -321,6 +353,11 @@ void SeqSourceProcessor::releaseAudio() {
 		SourceManager::getInstance()->releaseSource(this->audioSourceRef);
 		this->audioSourceRef = 0;
 	}
+
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
 }
 
 void SeqSourceProcessor::releaseMIDI() {
@@ -330,6 +367,11 @@ void SeqSourceProcessor::releaseMIDI() {
 		this->midiSourceRef = 0;
 	}
 	this->currentMIDITrack = 0;
+
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
 }
 
 void SeqSourceProcessor::applyAudioIfNeed() {
@@ -350,11 +392,21 @@ void SeqSourceProcessor::initAudio(double sampleRate, double length) {
 	this->applyAudio();
 	SourceManager::getInstance()->initAudio(this->audioSourceRef,
 		this->audioChannels.size(), sampleRate, length);
+
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
 }
 
 void SeqSourceProcessor::initMIDI() {
 	this->applyMIDI();
 	SourceManager::getInstance()->initMIDI(this->midiSourceRef);
+
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
 }
 
 const juce::String SeqSourceProcessor::getAudioFileName() const {
@@ -408,6 +460,11 @@ const juce::String SeqSourceProcessor::getMIDIName() const {
 void SeqSourceProcessor::setCurrentMIDITrack(int trackIndex) {
 	this->currentMIDITrack = trackIndex;
 
+	/** ARA Change */
+	if (auto plugin = this->getInstrProcessor()) {
+		plugin->invokeARADocumentChange();
+	}
+
 	/** Callback */
 	UICallbackAPI<int>::invoke(UICallbackType::SeqDataRefChanged, this->index);
 }
diff --git a/src/audioCore/source/SourceItem.cpp b/src/audioCore/source/SourceItem.cpp
index aa60bf4..9c675ef 100644
--- a/src/audioCore/source/SourceItem.cpp
+++ b/src/audioCore/source/SourceItem.cpp
@@ -282,7 +282,7 @@ void SourceItem::setCallback(const ChangedCallback& callback) {
 
 void SourceItem::invokeCallback() const {
 	if (this->callback) {
-		this->callback();
+		juce::MessageManager::callAsync(this->callback);
 	}
 }