diff --git a/src/lib/client/Client.cpp b/src/lib/client/Client.cpp
index 5919dab7..ff57d540 100644
--- a/src/lib/client/Client.cpp
+++ b/src/lib/client/Client.cpp
@@ -265,7 +265,11 @@ Client::leave()
 	m_screen->leave();
 
 	m_active = false;
-
+	
+	if (m_sendClipboardThread != NULL) {
+		StreamChunker::interruptClipboard();
+	}
+	
 	m_sendClipboardThread = new Thread(
 								new TMethodJob<Client>(
 									this,
@@ -803,6 +807,10 @@ Client::isReceivedFileSizeValid()
 void
 Client::sendFileToServer(const char* filename)
 {
+	if (m_sendFileThread != NULL) {
+		StreamChunker::interruptFile();
+	}
+	
 	m_sendFileThread = new Thread(
 		new TMethodJob<Client>(
 			this, &Client::sendFileThread,
diff --git a/src/lib/server/Server.cpp b/src/lib/server/Server.cpp
index 8c0574ef..832a03b0 100644
--- a/src/lib/server/Server.cpp
+++ b/src/lib/server/Server.cpp
@@ -505,7 +505,12 @@ Server::switchScreen(BaseClientProxy* dst,
 		m_active->enter(x, y, m_seqNum,
 								m_primaryClient->getToggleMask(),
 								forScreensaver);
-
+		// if already sending clipboard, we need to interupt it, otherwise
+		// clipboard data could be corrupted on the other side
+		if (m_sendClipboardThread != NULL) {
+			StreamChunker::interruptClipboard();
+		}
+		
 		// send the clipboard data to new active screen
 		m_sendClipboardThread = new Thread(
 										new TMethodJob<Server>(
@@ -2347,6 +2352,10 @@ Server::isReceivedFileSizeValid()
 void
 Server::sendFileToClient(const char* filename)
 {
+	if (m_sendFileThread != NULL) {
+		StreamChunker::interruptFile();
+	}
+	
 	m_sendFileThread = new Thread(
 		new TMethodJob<Server>(
 			this, &Server::sendFileThread,
diff --git a/src/lib/synergy/StreamChunker.cpp b/src/lib/synergy/StreamChunker.cpp
index 4058385e..46230ccd 100644
--- a/src/lib/synergy/StreamChunker.cpp
+++ b/src/lib/synergy/StreamChunker.cpp
@@ -39,6 +39,11 @@ using namespace std;
 #define SECURE_SOCKET_CHUNK_SIZE 2 * 1024; // 2kb
 
 size_t StreamChunker::s_chunkSize = SOCKET_CHUNK_SIZE;
+bool StreamChunker::s_isChunkingClipboard = false;
+bool StreamChunker::s_interruptClipboard = false;
+bool StreamChunker::s_isChunkingFile = false;
+bool StreamChunker::s_interruptFile = false;
+
 
 void
 StreamChunker::sendFile(
@@ -46,6 +51,8 @@ StreamChunker::sendFile(
 				IEventQueue* events,
 				void* eventTarget)
 {
+	s_isChunkingFile = true;
+	
 	std::fstream file(reinterpret_cast<char*>(filename), std::ios::in | std::ios::binary);
 
 	if (!file.is_open()) {
@@ -69,6 +76,11 @@ StreamChunker::sendFile(
 	stopwatch.start();
 	file.seekg (0, std::ios::beg);
 	while (true) {
+		if (s_interruptFile) {
+			s_interruptFile = false;
+			break;
+		}
+		
 		if (stopwatch.getTime() > PAUSE_TIME_HACK) {
 			// make sure we don't read too much from the mock data.
 			if (sentLength + chunkSize > size) {
@@ -100,6 +112,8 @@ StreamChunker::sendFile(
 	events->addEvent(Event(events->forIScreen().fileChunkSending(), eventTarget, end));
 
 	file.close();
+	
+	s_isChunkingFile = false;
 }
 
 void
@@ -111,6 +125,8 @@ StreamChunker::sendClipboard(
 				IEventQueue* events,
 				void* eventTarget)
 {
+	s_isChunkingClipboard = true;
+	
 	// send first message (data size)
 	String dataSize = synergy::string::sizeTypeToString(size);
 	ClipboardChunk* sizeMessage = ClipboardChunk::start(id, sequence, dataSize);
@@ -122,7 +138,13 @@ StreamChunker::sendClipboard(
 	size_t chunkSize = s_chunkSize;
 	Stopwatch stopwatch;
 	stopwatch.start();
+	
 	while (true) {
+		if (s_interruptClipboard) {
+			s_interruptClipboard = false;
+			break;
+		}
+		
 		if (stopwatch.getTime() > 0.1f) {
 			// make sure we don't read too much from the mock data.
 			if (sentLength + chunkSize > size) {
@@ -148,6 +170,8 @@ StreamChunker::sendClipboard(
 	ClipboardChunk* end = ClipboardChunk::end(id, sequence);
 
 	events->addEvent(Event(events->forClipboard().clipboardSending(), eventTarget, end));
+	
+	s_isChunkingClipboard = false;
 }
 
 void
@@ -160,3 +184,21 @@ StreamChunker::updateChunkSize(bool useSecureSocket)
 		s_chunkSize = SOCKET_CHUNK_SIZE;
 	}
 }
+
+void
+StreamChunker::interruptFile()
+{
+	if (s_isChunkingFile) {
+		s_interruptFile = true;
+		LOG((CLOG_INFO "previous dragged file has become invalid"));
+	}
+}
+
+void
+StreamChunker::interruptClipboard()
+{
+	if (s_isChunkingClipboard) {
+		s_interruptClipboard = true;
+		LOG((CLOG_INFO "previous clipboard data has become invalid"));
+	}
+}
diff --git a/src/lib/synergy/StreamChunker.h b/src/lib/synergy/StreamChunker.h
index a4be2714..b0bfb341 100644
--- a/src/lib/synergy/StreamChunker.h
+++ b/src/lib/synergy/StreamChunker.h
@@ -36,7 +36,13 @@ public:
 							IEventQueue* events,
 							void* eventTarget);
 	static void			updateChunkSize(bool useSecureSocket);
-
+	static void			interruptFile();
+	static void			interruptClipboard();
+	
 private:
-	static				size_t s_chunkSize;
+	static size_t		s_chunkSize;
+	static bool			s_isChunkingClipboard;
+	static bool			s_interruptClipboard;
+	static bool			s_isChunkingFile;
+	static bool			s_interruptFile;
 };