diff --git a/src/FFmpegReader.cpp b/src/FFmpegReader.cpp
index cba25cf7..ba3718e7 100644
--- a/src/FFmpegReader.cpp
+++ b/src/FFmpegReader.cpp
@@ -206,6 +206,9 @@ int FFmpegReader::IsHardwareDecodeSupported(int codecid)
 void FFmpegReader::Open() {
 	// Open reader if not already open
 	if (!is_open) {
+		// Prevent calls to GetFrame when Closing
+		const std::lock_guard<std::recursive_mutex> lock(processingMutex);
+
 		// Initialize format context
 		pFormatCtx = NULL;
 		{
@@ -2035,9 +2038,6 @@ std::shared_ptr<Frame> FFmpegReader::CreateFrame(int64_t requested_frame) {
 	std::shared_ptr<Frame> output = working_cache.GetFrame(requested_frame);
 
 	if (!output) {
-		// Lock
-		const std::lock_guard<std::recursive_mutex> lock(processingMutex);
-
 		// (re-)Check working cache
 		output = working_cache.GetFrame(requested_frame);
 		if(output) return output;
diff --git a/src/Timeline.cpp b/src/Timeline.cpp
index 52e8af3f..71253f48 100644
--- a/src/Timeline.cpp
+++ b/src/Timeline.cpp
@@ -772,7 +772,10 @@ void Timeline::sort_effects()
 void Timeline::Clear()
 {
     ZmqLogger::Instance()->AppendDebugMethod("Timeline::Clear");
-    
+
+	// Get lock (prevent getting frames while this happens)
+	const std::lock_guard<std::recursive_mutex> guard(getFrameMutex);
+
 	// Close all open clips
 	for (auto clip : clips)
 	{
@@ -1100,9 +1103,6 @@ Json::Value Timeline::JsonValue() const {
 // Load JSON string into this object
 void Timeline::SetJson(const std::string value) {
 
-	// Get lock (prevent getting frames while this happens)
-	const std::lock_guard<std::recursive_mutex> lock(getFrameMutex);
-
 	// Parse JSON string into JSON objects
 	try
 	{
@@ -1120,6 +1120,9 @@ void Timeline::SetJson(const std::string value) {
 // Load Json::Value into this object
 void Timeline::SetJsonValue(const Json::Value root) {
 
+	// Get lock (prevent getting frames while this happens)
+	const std::lock_guard<std::recursive_mutex> lock(getFrameMutex);
+
 	// Close timeline before we do anything (this closes all clips)
 	bool was_open = is_open;
 	Close();