diff --git a/ChangeLog b/ChangeLog
index 66ec45c16..0a7435ce1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -33,6 +33,7 @@ Bug fixes:
 - #6946 Add build stage to filename
 - #6950 Synergy client doesn't save the server address when rebooted
 - #6951 Fix issue creating standard version for Raspberry Pi
+- #6971 Fix vulnerabilities from SonarCloud
 
 Enhancements:
 - #6912 Removes UI for Screen Saver Sync and Files Drag and Drop
diff --git a/src/gui/src/QUtility.cpp b/src/gui/src/QUtility.cpp
index 34c0db961..38bba3be1 100644
--- a/src/gui/src/QUtility.cpp
+++ b/src/gui/src/QUtility.cpp
@@ -22,6 +22,7 @@
 
 #if defined(Q_OS_LINUX)
 #include <QProcess>
+#include <QFile>
 #endif
 
 #if defined(Q_OS_WIN)
@@ -48,20 +49,6 @@ QString hash(const QString& string)
     return hash.toHex();
 }
 
-QString getFirstMacAddress()
-{
-    QString mac;
-    foreach (const QNetworkInterface &interface,  QNetworkInterface::allInterfaces())
-    {
-        mac = interface.hardwareAddress();
-        if (mac.size() != 0)
-        {
-            break;
-        }
-    }
-    return mac;
-}
-
 qProcessorArch getProcessorArch()
 {
 #if defined(Q_OS_WIN)
@@ -90,26 +77,3 @@ qProcessorArch getProcessorArch()
 
     return kProcessorArchUnknown;
 }
-
-QString getOSInformation()
-{
-    QString result;
-
-#if defined(Q_OS_LINUX)
-    result = "Linux";
-    try {
-        QStringList arguments;
-        arguments.append("/etc/os-release");
-        CommandProcess cp("/bin/cat", arguments);
-        QString output = cp.run();
-
-        QRegExp resultRegex(".*PRETTY_NAME=\"([^\"]+)\".*");
-        if (resultRegex.exactMatch(output)) {
-            result = resultRegex.cap(1);
-        }
-    } catch (...) {
-    }
-#endif
-
-    return result;
-}
diff --git a/src/gui/src/QUtility.h b/src/gui/src/QUtility.h
index 0738d96cc..56e76bb88 100644
--- a/src/gui/src/QUtility.h
+++ b/src/gui/src/QUtility.h
@@ -26,6 +26,4 @@
 
 void setIndexFromItemData(QComboBox* comboBox, const QVariant& itemData);
 QString hash(const QString& string);
-QString getFirstMacAddress();
 qProcessorArch getProcessorArch();
-QString getOSInformation();
diff --git a/src/lib/arch/unix/ArchMultithreadPosix.cpp b/src/lib/arch/unix/ArchMultithreadPosix.cpp
index 23a348aac..958a19cdf 100644
--- a/src/lib/arch/unix/ArchMultithreadPosix.cpp
+++ b/src/lib/arch/unix/ArchMultithreadPosix.cpp
@@ -720,7 +720,7 @@ ArchMultithreadPosix::doThreadFunc(ArchThread thread)
     lockMutex(m_threadMutex);
     unlockMutex(m_threadMutex);
 
-    void* result = NULL;
+    void* result = nullptr;
     try {
         // go
         result = (*thread->m_func)(thread->m_userData);
@@ -728,6 +728,8 @@ ArchMultithreadPosix::doThreadFunc(ArchThread thread)
 
     catch (XThreadCancel&) {
         // client called cancel()
+        // set base value
+        result = nullptr;
     }
     catch (...) {
         // note -- don't catch (...) to avoid masking bugs
diff --git a/src/lib/base/XBase.cpp b/src/lib/base/XBase.cpp
index ee4b56655..cf51bc019 100644
--- a/src/lib/base/XBase.cpp
+++ b/src/lib/base/XBase.cpp
@@ -69,6 +69,7 @@ XBase::format(const char* /*id*/, const char* fmt, ...) const throw()
     }
     catch (...) {
         // ignore
+        result.clear();
     }
     va_end(args);
 
diff --git a/src/lib/net/SecureSocket.h b/src/lib/net/SecureSocket.h
index d2d275fab..e20c133a2 100644
--- a/src/lib/net/SecureSocket.h
+++ b/src/lib/net/SecureSocket.h
@@ -44,7 +44,7 @@ public:
     SecureSocket& operator=(SecureSocket &&) =delete;
 
     // ISocket overrides
-    void                close();
+    void                close() override;
 
     // IDataSocket overrides
     virtual void        connect(const NetworkAddress&);
diff --git a/src/lib/net/TCPListenSocket.cpp b/src/lib/net/TCPListenSocket.cpp
index 707f8fe23..32f2dcf58 100644
--- a/src/lib/net/TCPListenSocket.cpp
+++ b/src/lib/net/TCPListenSocket.cpp
@@ -28,6 +28,7 @@
 #include "mt/Mutex.h"
 #include "arch/Arch.h"
 #include "arch/XArch.h"
+#include "base/Log.h"
 #include "base/IEventQueue.h"
 
 //
@@ -57,6 +58,7 @@ TCPListenSocket::~TCPListenSocket()
     }
     catch (...) {
         // ignore
+        LOG((CLOG_WARN "error while closing TCP socket"));
     }
     delete m_mutex;
 }
diff --git a/src/lib/net/TCPSocket.cpp b/src/lib/net/TCPSocket.cpp
index bc7f28646..b9f226c73 100644
--- a/src/lib/net/TCPSocket.cpp
+++ b/src/lib/net/TCPSocket.cpp
@@ -47,7 +47,7 @@ TCPSocket::TCPSocket(IEventQueue* events, SocketMultiplexer* socketMultiplexer,
     try {
         m_socket = ARCH->newSocket(family, IArchNetwork::kSTREAM);
     }
-    catch (XArchNetwork& e) {
+    catch (const XArchNetwork& e) {
         throw XSocketCreate(e.what());
     }
 
@@ -64,7 +64,7 @@ TCPSocket::TCPSocket(IEventQueue* events, SocketMultiplexer* socketMultiplexer,
     m_flushed(&m_mutex, true),
     m_socketMultiplexer(socketMultiplexer)
 {
-    assert(m_socket != NULL);
+    assert(m_socket != nullptr);
 
     LOG((CLOG_DEBUG "Opening new socket: %08X", m_socket));
 
@@ -77,10 +77,11 @@ TCPSocket::TCPSocket(IEventQueue* events, SocketMultiplexer* socketMultiplexer,
 TCPSocket::~TCPSocket()
 {
     try {
+        // warning virtual function in destructor is very danger practice
         close();
     }
     catch (...) {
-        // ignore
+        LOG((CLOG_DEBUG "error while TCP socket destruction"));
     }
 }
 
@@ -90,10 +91,10 @@ TCPSocket::bind(const NetworkAddress& addr)
     try {
         ARCH->bindSocket(m_socket, addr.getAddress());
     }
-    catch (XArchNetworkAddressInUse& e) {
+    catch (const XArchNetworkAddressInUse& e) {
         throw XSocketAddressInUse(e.what());
     }
-    catch (XArchNetwork& e) {
+    catch (const XArchNetwork& e) {
         throw XSocketBind(e.what());
     }
 }
@@ -104,7 +105,7 @@ TCPSocket::close()
     LOG((CLOG_DEBUG "Closing socket: %08X", m_socket));
 
     // remove ourself from the multiplexer
-    setJob(NULL);
+    setJob(nullptr);
 
     Lock lock(&m_mutex);
 
@@ -115,13 +116,13 @@ TCPSocket::close()
     onDisconnected();
 
     // close the socket
-    if (m_socket != NULL) {
+    if (m_socket != nullptr) {
         ArchSocket socket = m_socket;
-        m_socket = NULL;
+        m_socket = nullptr;
         try {
             ARCH->closeSocket(socket);
         }
-        catch (XArchNetwork& e) {
+        catch (const XArchNetwork& e) {
             // ignore, there's not much we can do
             LOG((CLOG_WARN "error closing socket: %s", e.what()));
         }
@@ -143,7 +144,7 @@ TCPSocket::read(void* buffer, UInt32 n)
     if (n > size) {
         n = size;
     }
-    if (buffer != NULL && n != 0) {
+    if (buffer != nullptr && n != 0) {
         memcpy(buffer, m_inputBuffer.peek(n), n);
     }
     m_inputBuffer.pop(n);
@@ -209,8 +210,9 @@ TCPSocket::shutdownInput()
         try {
             ARCH->closeSocketForRead(m_socket);
         }
-        catch (XArchNetwork&) {
-            // ignore
+        catch (const XArchNetwork& e) {
+            // ignore, there's not much we can do
+            LOG((CLOG_WARN "error closing socket: %s", e.what()));
         }
 
         // shutdown buffer for reading
@@ -236,8 +238,9 @@ TCPSocket::shutdownOutput()
         try {
             ARCH->closeSocketForWrite(m_socket);
         }
-        catch (XArchNetwork&) {
-            // ignore
+        catch (const XArchNetwork& e) {
+            // ignore, there's not much we can do
+            LOG((CLOG_WARN "error closing socket: %s", e.what()));
         }
 
         // shutdown buffer for writing
@@ -281,7 +284,7 @@ TCPSocket::connect(const NetworkAddress& addr)
         Lock lock(&m_mutex);
 
         // fail on attempts to reconnect
-        if (m_socket == NULL || m_connected) {
+        if (m_socket == nullptr || m_connected) {
             sendConnectionFailedEvent("busy");
             return;
         }
@@ -296,7 +299,7 @@ TCPSocket::connect(const NetworkAddress& addr)
                 m_writable = true;
             }
         }
-        catch (XArchNetwork& e) {
+        catch (const XArchNetwork& e) {
             throw XSocketConnect(e.what());
         }
     }
@@ -317,13 +320,14 @@ TCPSocket::init()
         // mouse motion messages are much less useful if they're delayed.
         ARCH->setNoDelayOnSocket(m_socket, true);
     }
-    catch (XArchNetwork& e) {
+    catch (const XArchNetwork& e) {
         try {
             ARCH->closeSocket(m_socket);
-            m_socket = NULL;
+            m_socket = nullptr;
         }
-        catch (XArchNetwork&) {
-            // ignore
+        catch (const XArchNetwork& e) {
+            // ignore, there's not much we can do
+            LOG((CLOG_WARN "error closing socket: %s", e.what()));
         }
         throw XSocketCreate(e.what());
     }
@@ -392,7 +396,7 @@ void
 TCPSocket::setJob(ISocketMultiplexerJob* job)
 {
     // multiplexer will delete the old job
-    if (job == NULL) {
+    if (job == nullptr) {
         m_socketMultiplexer->removeSocket(this);
     }
     else {
@@ -405,13 +409,13 @@ TCPSocket::newJob()
 {
     // note -- must have m_mutex locked on entry
 
-    if (m_socket == NULL) {
-        return NULL;
+    if (m_socket == nullptr) {
+        return nullptr;
     }
     else if (!m_connected) {
         assert(!m_readable);
         if (!(m_readable || m_writable)) {
-            return NULL;
+            return nullptr;
         }
         return new TSocketMultiplexerMethodJob<TCPSocket>(
                                 this, &TCPSocket::serviceConnecting,
@@ -419,7 +423,7 @@ TCPSocket::newJob()
     }
     else {
         if (!(m_readable || (m_writable && (m_outputBuffer.getSize() > 0)))) {
-            return NULL;
+            return nullptr;
         }
         return new TSocketMultiplexerMethodJob<TCPSocket>(
                                 this, &TCPSocket::serviceConnected,
@@ -439,7 +443,7 @@ TCPSocket::sendConnectionFailedEvent(const char* msg)
 void
 TCPSocket::sendEvent(Event::Type type)
 {
-    m_events->addEvent(Event(type, getEventTarget(), NULL));
+    m_events->addEvent(Event(type, getEventTarget(), nullptr));
 }
 
 void
@@ -516,7 +520,7 @@ TCPSocket::serviceConnecting(ISocketMultiplexerJob* job,
             // connection may have failed or succeeded
             ARCH->throwErrorOnSocket(m_socket);
         }
-        catch (XArchNetwork& e) {
+        catch (const XArchNetwork& e) {
             sendConnectionFailedEvent(e.what());
             onDisconnected();
             return newJob();
@@ -592,5 +596,9 @@ TCPSocket::serviceConnected(ISocketMultiplexerJob* job,
         }
     }
 
-    return result == kBreak ? NULL : result == kNew ? newJob() : job;
+    if (result == kBreak) {
+        return nullptr;
+    }
+
+    return result == kNew ? newJob() : job;
 }
diff --git a/src/lib/platform/XWindowsClipboard.cpp b/src/lib/platform/XWindowsClipboard.cpp
index e0f6b19ef..17d4ed0c2 100644
--- a/src/lib/platform/XWindowsClipboard.cpp
+++ b/src/lib/platform/XWindowsClipboard.cpp
@@ -30,6 +30,7 @@
 #include "base/Stopwatch.h"
 #include "common/stdvector.h"
 
+#include <algorithm>
 #include <cstdio>
 #include <cstring>
 #include <X11/Xatom.h>
@@ -70,7 +71,6 @@ XWindowsClipboard::XWindowsClipboard(Display* display,
         m_selection = XInternAtom(m_display, "CLIPBOARD", False);
         break;
 
-    case kClipboardSelection:
     default:
         m_selection = XA_PRIMARY;
         break;
@@ -126,12 +126,10 @@ XWindowsClipboard::addRequest(Window owner, Window requestor,
     if (owner == m_window) {
         LOG((CLOG_DEBUG1 "request for clipboard %d, target %s by 0x%08x (property=%s)", m_selection, XWindowsUtil::atomToString(m_display, target).c_str(), requestor, XWindowsUtil::atomToString(m_display, property).c_str()));
         if (wasOwnedAtTime(time)) {
-            if (target == m_atomMultiple) {
+            if (target == m_atomMultiple && property != None) {
                 // add a multiple request.  property may not be None
                 // according to ICCCM.
-                if (property != None) {
-                    success = insertMultipleReply(requestor, time, property);
-                }
+                success = insertMultipleReply(requestor, time, property);
             }
             else {
                 addSimpleRequest(requestor, target, time, property);
@@ -178,7 +176,7 @@ XWindowsClipboard::addSimpleRequest(Window requestor,
     }
     else {
         IXWindowsClipboardConverter* converter = getConverter(target);
-        if (converter != NULL) {
+        if (converter != nullptr) {
             IClipboard::EFormat clipboardFormat = converter->getFormat();
             if (m_added[clipboardFormat]) {
                 try {
@@ -188,6 +186,7 @@ XWindowsClipboard::addSimpleRequest(Window requestor,
                 }
                 catch (...) {
                     // ignore -- cannot convert
+                    LOG((CLOG_WARN "error while converting clipboard data"));
                 }
             }
         }
@@ -406,7 +405,7 @@ XWindowsClipboard::clearConverters()
 IXWindowsClipboardConverter*
 XWindowsClipboard::getConverter(Atom target, bool onlyIfNotAdded) const
 {
-    IXWindowsClipboardConverter* converter = NULL;
+    IXWindowsClipboardConverter* converter = nullptr;
     for (ConverterList::const_iterator index = m_converters.begin();
                                 index != m_converters.end(); ++index) {
         converter = *index;
@@ -414,17 +413,15 @@ XWindowsClipboard::getConverter(Atom target, bool onlyIfNotAdded) const
             break;
         }
     }
-    if (converter == NULL) {
+    if (converter == nullptr) {
         LOG((CLOG_DEBUG1 "  no converter for target %s", XWindowsUtil::atomToString(m_display, target).c_str()));
-        return NULL;
+        return nullptr;
     }
 
     // optionally skip already handled targets
-    if (onlyIfNotAdded) {
-        if (m_added[converter->getFormat()]) {
-            LOG((CLOG_DEBUG1 "  skipping handled format %d", converter->getFormat()));
-            return NULL;
-        }
+    if (onlyIfNotAdded && m_added[converter->getFormat()]) {
+        LOG((CLOG_DEBUG1 "  skipping handled format %d", converter->getFormat()));
+        return nullptr;
     }
 
     return converter;
@@ -519,7 +516,7 @@ XWindowsClipboard::icccmFillCache()
     }
 
     XWindowsUtil::convertAtomProperty(data);
-    const Atom* targets = reinterpret_cast<const Atom*>(data.data()); // TODO: Safe?
+    auto targets            = static_cast<const Atom*>(static_cast<const void*>(data.data()));
     const UInt32 numTargets = data.size() / sizeof(Atom);
     LOG((CLOG_DEBUG "  available targets: %s", XWindowsUtil::atomsToString(m_display, targets, numTargets).c_str()));
 
@@ -572,8 +569,8 @@ bool
 XWindowsClipboard::icccmGetSelection(Atom target,
                 Atom* actualTarget, String* data) const
 {
-    assert(actualTarget != NULL);
-    assert(data         != NULL);
+    assert(actualTarget != nullptr);
+    assert(data         != nullptr);
 
     // request data conversion
     CICCCMGetClipboard getter(m_window, m_time, m_atomData);
@@ -597,7 +594,7 @@ XWindowsClipboard::icccmGetTime() const
     String data;
     if (icccmGetSelection(m_atomTimestamp, &actualTarget, &data) &&
         actualTarget == m_atomInteger) {
-        Time time = *reinterpret_cast<const Time*>(data.data());
+        Time time = *static_cast<const Time*>(static_cast<const void*>(data.data()));
         LOG((CLOG_DEBUG1 "got ICCCM time %d", time));
         return time;
     }
@@ -735,8 +732,7 @@ XWindowsClipboard::motifFillCache()
 
     // format list is after static item structure elements
     const SInt32 numFormats = item.m_numFormats - item.m_numDeletedFormats;
-    const SInt32* formats   = reinterpret_cast<const SInt32*>(item.m_size +
-                                static_cast<const char*>(data.data()));
+    auto formats            = static_cast<const SInt32*>(static_cast<const void*>(item.m_size + data.data()));
 
     // get the available formats
     typedef std::map<Atom, String> MotifFormatMap;
@@ -832,7 +828,7 @@ XWindowsClipboard::motifGetSelection(const MotifClipFormat* format,
     Window root = RootWindow(m_display, DefaultScreen(m_display));
     return XWindowsUtil::getWindowProperty(m_display, root,
                                 target, data,
-                                actualTarget, NULL, False);
+                                actualTarget, nullptr, False);
 }
 
 IClipboard::Time
@@ -862,7 +858,7 @@ XWindowsClipboard::insertMultipleReply(Window requestor,
 
     // data is a list of atom pairs:  target, property
     XWindowsUtil::convertAtomProperty(data);
-    const Atom* targets = reinterpret_cast<const Atom*>(data.data());
+    auto targets = static_cast<const Atom*>(static_cast<const void*>(data.data()));
     const UInt32 numTargets = data.size() / sizeof(Atom);
 
     // add replies for each target
@@ -894,7 +890,7 @@ XWindowsClipboard::insertMultipleReply(Window requestor,
 void
 XWindowsClipboard::insertReply(Reply* reply)
 {
-    assert(reply != NULL);
+    assert(reply != nullptr);
 
     // note -- we must respond to requests in order if requestor,target,time
     // are the same, otherwise we can use whatever order we like with one
@@ -995,7 +991,7 @@ XWindowsClipboard::pushReplies(ReplyMap::iterator& mapIndex,
 bool
 XWindowsClipboard::sendReply(Reply* reply)
 {
-    assert(reply != NULL);
+    assert(reply != nullptr);
 
     // bail out immediately if reply is done
     if (reply->m_done) {
@@ -1083,68 +1079,75 @@ XWindowsClipboard::sendReply(Reply* reply)
         }
     }
 
-    // send notification if we haven't yet
+    // notification already sended
     if (!reply->m_replied) {
-        LOG((CLOG_DEBUG1 "clipboard: sending notify to 0x%08x,%d,%d", reply->m_requestor, reply->m_target, reply->m_property));
-        reply->m_replied = true;
+        return false;
+        
+    }
 
-        // dump every property on the requestor window to the debug2
-        // log.  we've seen what appears to be a bug in lesstif and
-        // knowing the properties may help design a workaround, if
-        // it becomes necessary.
-        if (CLOG->getFilter() >= kDEBUG2) {
-            XWindowsUtil::ErrorLock lock(m_display);
-            int n;
-            Atom* props = XListProperties(m_display, reply->m_requestor, &n);
-            LOG((CLOG_DEBUG2 "properties of 0x%08x:", reply->m_requestor));
-            for (int i = 0; i < n; ++i) {
-                Atom target;
-                String data;
-                char* name = XGetAtomName(m_display, props[i]);
-                if (!XWindowsUtil::getWindowProperty(m_display,
-                                reply->m_requestor,
-                                props[i], &data, &target, NULL, False)) {
-                    LOG((CLOG_DEBUG2 "  %s: <can't read property>", name));
-                }
-                else {
-                    // if there are any non-ascii characters in string
-                    // then print the binary data.
-                    static const char* hex = "0123456789abcdef";
-                    String::size_type j = 0;
-                    while (j < data.size()) {
-                        if (data[j] < 32 || data[j] > 126) {
-                            String tmp;
-                            tmp.reserve(data.size() * 3);
-                            for (j = 0; j < data.size(); ++j) {
-                                unsigned char v = (unsigned char)data[j];
-                                tmp += hex[v >> 16];
-                                tmp += hex[v & 15];
-                                tmp += ' ';
-                            }
-                            data = tmp;
-                            break;
-                        }
-                        ++j;
-                    }
-                    char* type = XGetAtomName(m_display, target);
-                    LOG((CLOG_DEBUG2 "  %s (%s): %s", name, type, data.c_str()));
-                    if (type != NULL) {
-                        XFree(type);
-                    }
-                }
-                if (name != NULL) {
-                    XFree(name);
-                }
+    LOG((CLOG_DEBUG1 "clipboard: sending notify to 0x%08x,%d,%d", reply->m_requestor, reply->m_target, reply->m_property));
+    reply->m_replied = true;
+
+    // nothing to log
+    if (CLOG->getFilter() < kDEBUG2) {
+        sendNotify(reply->m_requestor, m_selection,
+                        reply->m_target, reply->m_property,
+                        static_cast<unsigned int>(reply->m_time));
+
+        // wait for delete notify
+        return false;
+        
+    }
+
+    // dump every property on the requestor window to the debug2
+    // log.  we've seen what appears to be a bug in lesstif and
+    // knowing the properties may help design a workaround, if
+    // it becomes necessary.
+    XWindowsUtil::ErrorLock lock(m_display);
+    int n;
+    Atom* props = XListProperties(m_display, reply->m_requestor, &n);
+    LOG((CLOG_DEBUG2 "properties of 0x%08x:", reply->m_requestor));
+    for (int i = 0; i < n; ++i) {
+        Atom target;
+        String data;
+        char* name = XGetAtomName(m_display, props[i]);
+        if (!XWindowsUtil::getWindowProperty(m_display,
+                        reply->m_requestor,
+                        props[i], &data, &target, nullptr, False)) {
+            LOG((CLOG_DEBUG2 "  %s: <can't read property>", name));
+        }
+        else {
+            // convert to hex if contains non ascii symbols
+            if (std::find_if(data.begin(), data.end(),
+                                    [](const unsigned char& c) { return c < 32 || c > 126; }) != data.end()) {
+                const String hex_digits = "0123456789abcdef";
+                String tmp;
+                tmp.reserve(data.length() * 3);
+                std::for_each(data.begin(), data.end(), [hex_digits, &tmp](const unsigned char& c)
+                    {
+                        tmp += hex_digits[c >> 16];
+                        tmp += hex_digits[c & 15];
+                        tmp += ' ';
+                    });
+                data = tmp;
             }
-            if (props != NULL) {
-                XFree(props);
+            char* type = XGetAtomName(m_display, target);
+            LOG((CLOG_DEBUG2 "  %s (%s): %s", name, type, data.c_str()));
+            if (type != nullptr) {
+                XFree(type);
             }
         }
-
-        sendNotify(reply->m_requestor, m_selection,
-                                reply->m_target, reply->m_property,
-                                reply->m_time);
+        if (name != nullptr) {
+            XFree(name);
+        }
     }
+    if (props != nullptr) {
+        XFree(props);
+    }
+
+    sendNotify(reply->m_requestor, m_selection,
+                            reply->m_target, reply->m_property,
+                            reply->m_time);
 
     // wait for delete notify
     return false;
@@ -1224,7 +1227,7 @@ XWindowsClipboard::wasOwnedAtTime(::Time time) const
 Atom
 XWindowsClipboard::getTargetsData(String& data, int* format) const
 {
-    assert(format != NULL);
+    assert(format != nullptr);
 
     // add standard targets
     XWindowsUtil::appendAtomData(data, m_atomTargets);
@@ -1249,7 +1252,7 @@ XWindowsClipboard::getTargetsData(String& data, int* format) const
 Atom
 XWindowsClipboard::getTimestampData(String& data, int* format) const
 {
-    assert(format != NULL);
+    assert(format != nullptr);
 
     checkCache();
     XWindowsUtil::appendTimeData(data, m_timeOwned);
@@ -1271,8 +1274,6 @@ XWindowsClipboard::CICCCMGetClipboard::CICCCMGetClipboard(
     m_failed(false),
     m_done(false),
     m_reading(false),
-    m_data(NULL),
-    m_actualTarget(NULL),
     m_error(false)
 {
     // do nothing
@@ -1287,8 +1288,8 @@ bool
 XWindowsClipboard::CICCCMGetClipboard::readClipboard(Display* display,
                 Atom selection, Atom target, Atom* actualTarget, String* data)
 {
-    assert(actualTarget != NULL);
-    assert(data         != NULL);
+    assert(actualTarget != nullptr);
+    assert(data         != nullptr);
 
     LOG((CLOG_DEBUG1 "request selection=%s, target=%s, window=%x", XWindowsUtil::atomToString(display, selection).c_str(), XWindowsUtil::atomToString(display, target).c_str(), m_requestor));
 
@@ -1438,7 +1439,7 @@ XWindowsClipboard::CICCCMGetClipboard::processEvent(
     Atom target;
     const String::size_type oldSize = m_data->size();
     if (!XWindowsUtil::getWindowProperty(display, m_requestor,
-                                m_property, m_data, &target, NULL, True)) {
+                                m_property, m_data, &target, nullptr, True)) {
         // unable to read property
         m_failed = true;
         return true;
@@ -1448,11 +1449,7 @@ XWindowsClipboard::CICCCMGetClipboard::processEvent(
     // selection owner is busted.  if the INCR property has no size
     // then the selection owner is busted.
     if (target == m_atomIncr) {
-        if (m_incr) {
-            m_failed = true;
-            m_error  = true;
-        }
-        else if (m_data->size() == oldSize) {
+        if (m_incr || m_data->size() == oldSize) {
             m_failed = true;
             m_error  = true;
         }
diff --git a/src/lib/platform/XWindowsClipboard.h b/src/lib/platform/XWindowsClipboard.h
index 66cf21fe9..fe088ffd2 100644
--- a/src/lib/platform/XWindowsClipboard.h
+++ b/src/lib/platform/XWindowsClipboard.h
@@ -172,11 +172,11 @@ private:
         bool            m_reading;
 
         // the converted selection data
-        String*        m_data;
+        String*        m_data = nullptr;
 
         // the actual type of the data.  if this is None then the
         // selection owner cannot convert to the requested type.
-        Atom*            m_actualTarget;
+        Atom*            m_actualTarget = nullptr;
 
     public:
         // true iff the selection owner didn't follow ICCCM conventions