diff --git a/src/gui/src/DataDownloader.cpp b/src/gui/src/DataDownloader.cpp
index 50e5a1b2..4f778489 100644
--- a/src/gui/src/DataDownloader.cpp
+++ b/src/gui/src/DataDownloader.cpp
@@ -19,6 +19,7 @@
 
 DataDownloader::DataDownloader(QObject* parent) :
     QObject(parent),
+    m_pReply(nullptr),
     m_IsFinished(false)
 {
     connect(&m_NetworkManager, SIGNAL(finished(QNetworkReply*)),
diff --git a/src/gui/src/ScreenSetupView.cpp b/src/gui/src/ScreenSetupView.cpp
index a06dc269..f26d9700 100644
--- a/src/gui/src/ScreenSetupView.cpp
+++ b/src/gui/src/ScreenSetupView.cpp
@@ -38,7 +38,7 @@ ScreenSetupView::ScreenSetupView(QWidget* parent) :
     verticalHeader()->hide();
 }
 
-void ScreenSetupView::setModel(ScreenSetupModel* model)
+void ScreenSetupView::setModel(QAbstractItemModel* model)
 {
     QTableView::setModel(model);
     setTableSize();
diff --git a/src/gui/src/ScreenSetupView.h b/src/gui/src/ScreenSetupView.h
index a4f04923..38eae2a4 100644
--- a/src/gui/src/ScreenSetupView.h
+++ b/src/gui/src/ScreenSetupView.h
@@ -39,7 +39,7 @@ class ScreenSetupView : public QTableView
         ScreenSetupView(QWidget* parent);
 
     public:
-        void setModel(ScreenSetupModel* model);
+        void setModel(QAbstractItemModel* model) override;
         ScreenSetupModel* model() const;
 
     protected:
diff --git a/src/gui/src/ZeroconfServer.cpp b/src/gui/src/ZeroconfServer.cpp
index d3d98518..e4d6dfd8 100644
--- a/src/gui/src/ZeroconfServer.cpp
+++ b/src/gui/src/ZeroconfServer.cpp
@@ -25,7 +25,7 @@ ZeroconfServer::ZeroconfServer(QObject* parent) :
 {
 }
 
-void ZeroconfServer::incomingConnection(int socketDescriptor)
+void ZeroconfServer::incomingConnection(qintptr socketDescriptor)
 {
     ZeroconfThread* thread = new ZeroconfThread(socketDescriptor, this);
     connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
diff --git a/src/gui/src/ZeroconfServer.h b/src/gui/src/ZeroconfServer.h
index 01e713d7..2f6c6f11 100644
--- a/src/gui/src/ZeroconfServer.h
+++ b/src/gui/src/ZeroconfServer.h
@@ -30,7 +30,7 @@ public:
     ZeroconfServer(QObject* parent = 0);
 
 protected:
-    void incomingConnection(int socketDescriptor);
+    void incomingConnection(qintptr socketDescriptor) override;
 
 private:
     QStringList fortunes;
diff --git a/src/lib/arch/IArchString.cpp b/src/lib/arch/IArchString.cpp
index 05cc2dfb..57365363 100644
--- a/src/lib/arch/IArchString.cpp
+++ b/src/lib/arch/IArchString.cpp
@@ -42,7 +42,7 @@ int
 IArchString::convStringWCToMB(char* dst,
                 const wchar_t* src, UInt32 n, bool* errors)
 {
-    int len = 0;
+    ptrdiff_t len = 0;
 
     bool dummyErrors;
     if (errors == NULL) {
@@ -58,14 +58,14 @@ IArchString::convStringWCToMB(char* dst,
     if (dst == NULL) {
         char dummy[MB_LEN_MAX];
         for (const wchar_t* scan = src; n > 0; ++scan, --n) {
-            int mblen = wctomb(dummy, *scan);
+            ptrdiff_t mblen = wctomb(dummy, *scan);
             if (mblen == -1) {
                 *errors = true;
                 mblen   = 1;
             }
             len += mblen;
         }
-        int mblen = wctomb(dummy, L'\0');
+        ptrdiff_t mblen = wctomb(dummy, L'\0');
         if (mblen != -1) {
             len += mblen - 1;
         }
@@ -73,7 +73,7 @@ IArchString::convStringWCToMB(char* dst,
     else {
         char* dst0 = dst;
         for (const wchar_t* scan = src; n > 0; ++scan, --n) {
-            int mblen = wctomb(dst, *scan);
+            ptrdiff_t mblen = wctomb(dst, *scan);
             if (mblen == -1) {
                 *errors = true;
                 *dst++  = '?';
@@ -82,12 +82,12 @@ IArchString::convStringWCToMB(char* dst,
                 dst    += mblen;
             }
         }
-        int mblen = wctomb(dst, L'\0');
+        ptrdiff_t mblen = wctomb(dst, L'\0');
         if (mblen != -1) {
             // don't include nul terminator
             dst += mblen - 1;
         }
-        len = (int)(dst - dst0);
+        len = dst - dst0;
     }
     ARCH->unlockMutex(s_mutex);
 
@@ -98,7 +98,7 @@ int
 IArchString::convStringMBToWC(wchar_t* dst,
                 const char* src, UInt32 n, bool* errors)
 {
-    int len = 0;
+    ptrdiff_t len = 0;
     wchar_t dummy;
 
     bool dummyErrors;
@@ -114,7 +114,7 @@ IArchString::convStringMBToWC(wchar_t* dst,
 
     if (dst == NULL) {
         for (const char* scan = src; n > 0; ) {
-            int mblen = mbtowc(&dummy, scan, n);
+            ptrdiff_t mblen = mbtowc(&dummy, scan, n);
             switch (mblen) {
             case -2:
                 // incomplete last character.  convert to unknown character.
@@ -150,7 +150,7 @@ IArchString::convStringMBToWC(wchar_t* dst,
     else {
         wchar_t* dst0 = dst;
         for (const char* scan = src; n > 0; ++dst) {
-            int mblen = mbtowc(dst, scan, n);
+            ptrdiff_t mblen = mbtowc(dst, scan, n);
             switch (mblen) {
             case -2:
                 // incomplete character.  convert to unknown character.
@@ -181,7 +181,7 @@ IArchString::convStringMBToWC(wchar_t* dst,
                 break;
             }
         }
-        len = (int)(dst - dst0);
+        len = dst - dst0;
     }
     ARCH->unlockMutex(s_mutex);
 
diff --git a/src/lib/arch/win32/ArchNetworkWinsock.cpp b/src/lib/arch/win32/ArchNetworkWinsock.cpp
index 24310402..65a5b320 100644
--- a/src/lib/arch/win32/ArchNetworkWinsock.cpp
+++ b/src/lib/arch/win32/ArchNetworkWinsock.cpp
@@ -311,7 +311,7 @@ ArchNetworkWinsock::listenOnSocket(ArchSocket s)
 }
 
 ArchSocket
-ArchNetworkWinsock::acceptSocket(ArchSocket s, ArchNetAddress* addr)
+ArchNetworkWinsock::acceptSocket(ArchSocket s, ArchNetAddress* const addr)
 {
     assert(s != NULL);
 
@@ -325,7 +325,9 @@ ArchNetworkWinsock::acceptSocket(ArchSocket s, ArchNetAddress* addr)
         int err = getsockerror_winsock();
         delete socket;
         free(tmp);
-        *addr = NULL;
+        if (addr) {
+            *addr = NULL;
+        }
         if (err == WSAEWOULDBLOCK) {
             return NULL;
         }
@@ -339,7 +341,9 @@ ArchNetworkWinsock::acceptSocket(ArchSocket s, ArchNetAddress* addr)
         close_winsock(fd);
         delete socket;
         free(tmp);
-        *addr = NULL;
+        if (addr) {
+            *addr = NULL;
+        }
         throw;
     }
 
diff --git a/src/lib/arch/win32/ArchTaskBarWindows.cpp b/src/lib/arch/win32/ArchTaskBarWindows.cpp
index 3ec3b21b..61376674 100644
--- a/src/lib/arch/win32/ArchTaskBarWindows.cpp
+++ b/src/lib/arch/win32/ArchTaskBarWindows.cpp
@@ -39,10 +39,14 @@ static const UINT        kFirstReceiverID = WM_USER + 14;
 ArchTaskBarWindows*    ArchTaskBarWindows::s_instance    = NULL;
 
 ArchTaskBarWindows::ArchTaskBarWindows() :
-    m_nextID(kFirstReceiverID),
-    m_thread(NULL),
+    m_mutex(NULL),
     m_condVar(NULL),
-    m_mutex(NULL)
+    m_ready(false),
+    m_result(0),
+    m_thread(NULL),
+    m_hwnd(NULL),
+    m_taskBarRestart(0),
+    m_nextID(kFirstReceiverID)
 {
     // save the singleton instance
     s_instance    = this;
diff --git a/src/lib/base/String.cpp b/src/lib/base/String.cpp
index e1da621f..8349715b 100644
--- a/src/lib/base/String.cpp
+++ b/src/lib/base/String.cpp
@@ -30,6 +30,7 @@
 #include <sstream>
 #include <iomanip>
 #include <algorithm>
+#include <cerrno>
 
 namespace synergy {
 namespace string {
@@ -50,8 +51,8 @@ vformat(const char* fmt, va_list args)
     // find highest indexed substitution and the locations of substitutions
     std::vector<size_t> pos;
     std::vector<size_t> width;
-    std::vector<int> index;
-    int maxIndex = 0;
+    std::vector<size_t> index;
+    size_t maxIndex = 0;
     for (const char* scan = fmt; *scan != '\0'; ++scan) {
         if (*scan == '%') {
             ++scan;
@@ -61,21 +62,22 @@ vformat(const char* fmt, va_list args)
             else if (*scan == '%') {
                 // literal
                 index.push_back(0);
-                pos.push_back(static_cast<int>(scan - 1 - fmt));
+                pos.push_back(static_cast<size_t>((scan - 1) - fmt));
                 width.push_back(2);
             }
             else if (*scan == '{') {
                 // get argument index
                 char* end;
-                int i = static_cast<int>(strtol(scan + 1, &end, 10));
-                if (*end != '}') {
+                errno = 0;
+                long i = strtol(scan + 1, &end, 10);
+                if (errno || (i < 0) || (*end != '}')) {
                     // invalid index -- ignore
-                    scan = end - 1;
+                    scan = end - 1; // BUG if there are digits?
                 }
                 else {
                     index.push_back(i);
-                    pos.push_back(static_cast<int>(scan - 1 - fmt));
-                    width.push_back(static_cast<int>(end - scan + 2));
+                    pos.push_back(static_cast<size_t>((scan - 1) - fmt));
+                    width.push_back(static_cast<size_t>((end - scan) + 2));
                     if (i > maxIndex) {
                         maxIndex = i;
                     }
diff --git a/src/lib/ipc/IpcLogOutputter.cpp b/src/lib/ipc/IpcLogOutputter.cpp
index f215750a..120fd66f 100644
--- a/src/lib/ipc/IpcLogOutputter.cpp
+++ b/src/lib/ipc/IpcLogOutputter.cpp
@@ -45,6 +45,7 @@ IpcLogOutputter::IpcLogOutputter(IpcServer& ipcServer, EIpcClientType clientType
     m_running(false),
     m_notifyCond(ARCH->newCondVar()),
     m_notifyMutex(ARCH->newMutex()),
+    m_bufferThreadId(0),
     m_bufferWaiting(false),
     m_bufferMaxSize(kBufferMaxSize),
     m_bufferRateWriteLimit(kBufferRateWriteLimit),
diff --git a/src/lib/ipc/IpcLogOutputter.h b/src/lib/ipc/IpcLogOutputter.h
index dd2bada6..b6b285b8 100644
--- a/src/lib/ipc/IpcLogOutputter.h
+++ b/src/lib/ipc/IpcLogOutputter.h
@@ -114,7 +114,6 @@ private:
     double                m_bufferRateTimeLimit;
     UInt16                m_bufferWriteCount;
     double                m_bufferRateStart;
-    bool                m_useThread;
     EIpcClientType        m_clientType;
     ArchMutex            m_runningMutex;
 };
diff --git a/src/lib/ipc/IpcServer.cpp b/src/lib/ipc/IpcServer.cpp
index 390310ec..791595f2 100644
--- a/src/lib/ipc/IpcServer.cpp
+++ b/src/lib/ipc/IpcServer.cpp
@@ -80,7 +80,7 @@ IpcServer::~IpcServer()
     for (it = m_clients.begin(); it != m_clients.end(); it++) {
         deleteClient(*it);
     }
-    m_clients.empty();
+    m_clients.clear();
     ARCH->unlockMutex(m_clientsMutex);
     ARCH->closeMutex(m_clientsMutex);
     
diff --git a/src/lib/net/SecureSocket.cpp b/src/lib/net/SecureSocket.cpp
index c190750b..9dd3a816 100644
--- a/src/lib/net/SecureSocket.cpp
+++ b/src/lib/net/SecureSocket.cpp
@@ -57,6 +57,7 @@ SecureSocket::SecureSocket(
         IEventQueue* events,
         SocketMultiplexer* socketMultiplexer) :
     TCPSocket(events, socketMultiplexer),
+    m_ssl(nullptr),
     m_secureReady(false),
     m_fatal(false)
 {
@@ -67,6 +68,7 @@ SecureSocket::SecureSocket(
         SocketMultiplexer* socketMultiplexer,
         ArchSocket socket) :
     TCPSocket(events, socketMultiplexer, socket),
+    m_ssl(nullptr),
     m_secureReady(false),
     m_fatal(false)
 {
diff --git a/src/lib/net/TCPSocket.cpp b/src/lib/net/TCPSocket.cpp
index 9498e946..ff69ab2b 100644
--- a/src/lib/net/TCPSocket.cpp
+++ b/src/lib/net/TCPSocket.cpp
@@ -330,7 +330,7 @@ TCPSocket::doRead()
     memset(buffer, 0, sizeof(buffer));
     size_t bytesRead = 0;
     
-    bytesRead = (int) ARCH->readSocket(m_socket, buffer, sizeof(buffer));
+    bytesRead = ARCH->readSocket(m_socket, buffer, sizeof(buffer));
     
     if (bytesRead > 0) {
         bool wasEmpty = (m_inputBuffer.getSize() == 0);
diff --git a/src/lib/platform/MSWindowsClipboard.cpp b/src/lib/platform/MSWindowsClipboard.cpp
index 2373d255..5a807a0c 100644
--- a/src/lib/platform/MSWindowsClipboard.cpp
+++ b/src/lib/platform/MSWindowsClipboard.cpp
@@ -88,7 +88,11 @@ MSWindowsClipboard::empty()
 
     // mark clipboard as being owned by synergy
     HGLOBAL data = GlobalAlloc(GMEM_MOVEABLE | GMEM_DDESHARE, 1);
-    SetClipboardData(getOwnershipFormat(), data);
+    if (NULL == SetClipboardData(getOwnershipFormat(), data)) {
+        LOG((CLOG_DEBUG "failed to set clipboard data"));
+        GlobalFree(data);
+        return false;
+    }
 
     return true;
 }
diff --git a/src/lib/platform/MSWindowsDesks.cpp b/src/lib/platform/MSWindowsDesks.cpp
index 325e4578..c377ab76 100644
--- a/src/lib/platform/MSWindowsDesks.cpp
+++ b/src/lib/platform/MSWindowsDesks.cpp
@@ -427,7 +427,7 @@ void
 MSWindowsDesks::destroyClass(ATOM windowClass) const
 {
     if (windowClass != 0) {
-        UnregisterClass(reinterpret_cast<LPCTSTR>(windowClass),
+        UnregisterClass(MAKEINTATOM(windowClass),
                             MSWindowsScreen::getWindowInstance());
     }
 }
@@ -437,7 +437,7 @@ MSWindowsDesks::createWindow(ATOM windowClass, const char* name) const
 {
     HWND window = CreateWindowEx(WS_EX_TRANSPARENT |
                                     WS_EX_TOOLWINDOW,
-                                reinterpret_cast<LPCTSTR>(windowClass),
+                                MAKEINTATOM(windowClass),
                                 name,
                                 WS_POPUP,
                                 0, 0, 1, 1,
diff --git a/src/lib/platform/MSWindowsScreen.cpp b/src/lib/platform/MSWindowsScreen.cpp
index bcb794e1..080db53d 100644
--- a/src/lib/platform/MSWindowsScreen.cpp
+++ b/src/lib/platform/MSWindowsScreen.cpp
@@ -858,7 +858,7 @@ void
 MSWindowsScreen::destroyClass(ATOM windowClass) const
 {
     if (windowClass != 0) {
-        UnregisterClass(reinterpret_cast<LPCTSTR>(windowClass), s_windowInstance);
+        UnregisterClass(MAKEINTATOM(windowClass), s_windowInstance);
     }
 }
 
@@ -868,7 +868,7 @@ MSWindowsScreen::createWindow(ATOM windowClass, const char* name) const
     HWND window = CreateWindowEx(WS_EX_TOPMOST |
                                     WS_EX_TRANSPARENT |
                                     WS_EX_TOOLWINDOW,
-                                reinterpret_cast<LPCTSTR>(windowClass),
+                                MAKEINTATOM(windowClass),
                                 name,
                                 WS_POPUP,
                                 0, 0, 1, 1,
@@ -889,7 +889,7 @@ MSWindowsScreen::createDropWindow(ATOM windowClass, const char* name) const
         WS_EX_TOPMOST |
         WS_EX_TRANSPARENT |
         WS_EX_ACCEPTFILES,
-        reinterpret_cast<LPCTSTR>(m_class),
+        MAKEINTATOM(m_class),
         name,
         WS_POPUP,
         0, 0, m_dropWindowSize, m_dropWindowSize,
@@ -1129,7 +1129,7 @@ MSWindowsScreen::onKey(WPARAM wParam, LPARAM lParam)
     KeyModifierMask oldState = pollActiveModifiers();
 
     // check for autorepeat
-    if (m_keyState->testAutoRepeat(down, (lParam & 0x40000000u) == 1, button)) {
+    if (m_keyState->testAutoRepeat(down, (lParam & 0x40000000u), button)) {
         lParam |= 0x40000000u;
     }
 
diff --git a/src/lib/platform/MSWindowsScreenSaver.cpp b/src/lib/platform/MSWindowsScreenSaver.cpp
index f6a9d386..96771b27 100644
--- a/src/lib/platform/MSWindowsScreenSaver.cpp
+++ b/src/lib/platform/MSWindowsScreenSaver.cpp
@@ -50,6 +50,9 @@ MSWindowsScreenSaver::MSWindowsScreenSaver() :
     m_process(NULL),
     m_watch(NULL),
     m_threadID(0),
+    m_msg(0),
+    m_wParam(0),
+    m_lParam(0),
     m_active(false)
 {
     // check if screen saver is enabled
diff --git a/src/lib/platform/MSWindowsSession.cpp b/src/lib/platform/MSWindowsSession.cpp
index 9e817b1e..b70de74c 100644
--- a/src/lib/platform/MSWindowsSession.cpp
+++ b/src/lib/platform/MSWindowsSession.cpp
@@ -187,7 +187,7 @@ MSWindowsSession::getActiveDesktopName()
             CloseDesktop(hd);
         }
     }
-    catch (std::exception error) {
+    catch (std::exception& error) {
         LOG((CLOG_ERR "failed to get active desktop name: %s", error.what()));
     }
 
diff --git a/src/lib/platform/MSWindowsUtil.cpp b/src/lib/platform/MSWindowsUtil.cpp
index 811c6be2..7ce6e2dc 100644
--- a/src/lib/platform/MSWindowsUtil.cpp
+++ b/src/lib/platform/MSWindowsUtil.cpp
@@ -29,31 +29,14 @@
 String
 MSWindowsUtil::getString(HINSTANCE instance, DWORD id)
 {
-    char buffer[1024];
-    int size = static_cast<int>(sizeof(buffer) / sizeof(buffer[0]));
-    char* msg = buffer;
+    char* msg = NULL;
+    int n = LoadString(instance, id, reinterpret_cast<LPSTR>(&msg), 0);
 
-    // load string
-    int n = LoadString(instance, id, msg, size);
-    msg[n] = '\0';
-    if (n < size) {
-        return msg;
+    if (n <= 0) {
+        return String();
     }
 
-    // not enough buffer space.  keep trying larger buffers until
-    // we get the whole string.
-    msg = NULL;
-    do {
-        size <<= 1;
-        delete[] msg;
-        char* msg = new char[size];
-        n = LoadString(instance, id, msg, size);
-    } while (n == size);
-    msg[n] = '\0';
-
-    String result(msg);
-    delete[] msg;
-    return result;
+    return String (msg, n);
 }
 
 String
diff --git a/src/lib/synergy/App.cpp b/src/lib/synergy/App.cpp
index 81ab826c..4c8c1808 100644
--- a/src/lib/synergy/App.cpp
+++ b/src/lib/synergy/App.cpp
@@ -62,9 +62,11 @@ App::App(IEventQueue* events, CreateTaskBarReceiverFunc createTaskBarReceiver, A
     m_suspended(false),
     m_events(events),
     m_args(args),
+    m_fileLog(nullptr),
     m_createTaskBarReceiver(createTaskBarReceiver),
     m_appUtil(events),
-    m_ipcClient(nullptr)
+    m_ipcClient(nullptr),
+    m_socketMultiplexer(nullptr)
 {
     assert(s_instance == nullptr);
     s_instance = this;
diff --git a/src/lib/synergy/Chunk.cpp b/src/lib/synergy/Chunk.cpp
index 0bd8a62c..71464f70 100644
--- a/src/lib/synergy/Chunk.cpp
+++ b/src/lib/synergy/Chunk.cpp
@@ -18,7 +18,7 @@
 #include "synergy/Chunk.h"
 #include "base/String.h"
 
-Chunk::Chunk(size_t size)
+Chunk::Chunk(size_t size): m_dataSize(0)
 {
     m_chunk = new char[size];
     memset(m_chunk, 0, size);