diff --git a/src/app/application.cpp b/src/app/application.cpp
index c50c82a4b..47c0431c3 100644
--- a/src/app/application.cpp
+++ b/src/app/application.cpp
@@ -224,7 +224,6 @@ namespace
 
 Application::Application(int &argc, char **argv)
     : BaseApplication(argc, argv)
-    , m_shutdownAct(ShutdownDialogAction::Exit)
     , m_commandLineArgs(parseCommandLine(Application::arguments()))
     , m_storeFileLoggerEnabled(FILELOGGER_SETTINGS_KEY(u"Enabled"_qs))
     , m_storeFileLoggerBackup(FILELOGGER_SETTINGS_KEY(u"Backup"_qs))
diff --git a/src/app/application.h b/src/app/application.h
index e7f1b1d14..ee69f5afc 100644
--- a/src/app/application.h
+++ b/src/app/application.h
@@ -173,7 +173,7 @@ private:
     ApplicationInstanceManager *m_instanceManager = nullptr;
     QAtomicInt m_isCleanupRun;
     bool m_isProcessingParamsAllowed = false;
-    ShutdownDialogAction m_shutdownAct;
+    ShutdownDialogAction m_shutdownAct = ShutdownDialogAction::Exit;
     QBtCommandLineParameters m_commandLineArgs;
 
     // FileLog
diff --git a/src/base/bittorrent/bandwidthscheduler.cpp b/src/base/bittorrent/bandwidthscheduler.cpp
index ca4c5d5a3..bb8d1d0a8 100644
--- a/src/base/bittorrent/bandwidthscheduler.cpp
+++ b/src/base/bittorrent/bandwidthscheduler.cpp
@@ -41,7 +41,6 @@ using namespace std::chrono_literals;
 
 BandwidthScheduler::BandwidthScheduler(QObject *parent)
     : QObject(parent)
-    , m_lastAlternative(false)
 {
     connect(&m_timer, &QTimer::timeout, this, &BandwidthScheduler::onTimeout);
 }
diff --git a/src/base/bittorrent/bandwidthscheduler.h b/src/base/bittorrent/bandwidthscheduler.h
index ecbb43d8d..00eebe7ad 100644
--- a/src/base/bittorrent/bandwidthscheduler.h
+++ b/src/base/bittorrent/bandwidthscheduler.h
@@ -49,5 +49,5 @@ private:
     void onTimeout();
 
     QTimer m_timer;
-    bool m_lastAlternative;
+    bool m_lastAlternative = false;
 };
diff --git a/src/base/bittorrent/filterparserthread.cpp b/src/base/bittorrent/filterparserthread.cpp
index cdd8f88b1..3b92396f2 100644
--- a/src/base/bittorrent/filterparserthread.cpp
+++ b/src/base/bittorrent/filterparserthread.cpp
@@ -89,7 +89,7 @@ namespace
         }
 
     private:
-        lt::address_v4::bytes_type m_buf;
+        lt::address_v4::bytes_type m_buf {};
     };
 
     bool parseIPAddress(const char *data, lt::address &address)
@@ -111,7 +111,6 @@ namespace
 
 FilterParserThread::FilterParserThread(QObject *parent)
     : QThread(parent)
-    , m_abort(false)
 {
 }
 
diff --git a/src/base/bittorrent/filterparserthread.h b/src/base/bittorrent/filterparserthread.h
index b118d706e..2b734a555 100644
--- a/src/base/bittorrent/filterparserthread.h
+++ b/src/base/bittorrent/filterparserthread.h
@@ -62,7 +62,7 @@ private:
     int getlineInStream(QDataStream &stream, std::string &name, char delim);
     int parseP2BFilterFile();
 
-    bool m_abort;
+    bool m_abort = false;
     Path m_filePath;
     lt::ip_filter m_filter;
 };
diff --git a/src/base/bittorrent/loadtorrentparams.h b/src/base/bittorrent/loadtorrentparams.h
index 1ebbcfe47..68932c609 100644
--- a/src/base/bittorrent/loadtorrentparams.h
+++ b/src/base/bittorrent/loadtorrentparams.h
@@ -54,7 +54,7 @@ namespace BitTorrent
         bool firstLastPiecePriority = false;
         bool hasFinishedStatus = false;
         bool stopped = false;
-        Torrent::StopCondition stopCondition;
+        Torrent::StopCondition stopCondition = Torrent::StopCondition::None;
 
         bool addToQueueTop = false; // only for new torrents
 
diff --git a/src/base/bittorrent/magneturi.cpp b/src/base/bittorrent/magneturi.cpp
index dba8bb392..2c0154bce 100644
--- a/src/base/bittorrent/magneturi.cpp
+++ b/src/base/bittorrent/magneturi.cpp
@@ -75,8 +75,7 @@ using namespace BitTorrent;
 const int magnetUriId = qRegisterMetaType<MagnetUri>();
 
 MagnetUri::MagnetUri(const QString &source)
-    : m_valid(false)
-    , m_url(source)
+    : m_url(source)
 {
     if (source.isEmpty()) return;
 
diff --git a/src/base/bittorrent/magneturi.h b/src/base/bittorrent/magneturi.h
index 861ce53b2..f0becd129 100644
--- a/src/base/bittorrent/magneturi.h
+++ b/src/base/bittorrent/magneturi.h
@@ -54,7 +54,7 @@ namespace BitTorrent
         lt::add_torrent_params addTorrentParams() const;
 
     private:
-        bool m_valid;
+        bool m_valid = false;
         QString m_url;
         InfoHash m_infoHash;
         QString m_name;
diff --git a/src/base/bittorrent/sessionimpl.h b/src/base/bittorrent/sessionimpl.h
index 449a7f44e..8a7af77ba 100644
--- a/src/base/bittorrent/sessionimpl.h
+++ b/src/base/bittorrent/sessionimpl.h
@@ -482,15 +482,15 @@ namespace BitTorrent
         {
             lt::torrent_handle torrentHandle;
             Path path;
-            MoveStorageMode mode;
-            MoveStorageContext context;
+            MoveStorageMode mode {};
+            MoveStorageContext context {};
         };
 
         struct RemovingTorrentData
         {
             QString name;
             Path pathToRemove;
-            DeleteOption deleteOption;
+            DeleteOption deleteOption {};
         };
 
         explicit SessionImpl(QObject *parent = nullptr);
diff --git a/src/base/bittorrent/torrentcreatorthread.h b/src/base/bittorrent/torrentcreatorthread.h
index 02b33f79b..31afeeb0c 100644
--- a/src/base/bittorrent/torrentcreatorthread.h
+++ b/src/base/bittorrent/torrentcreatorthread.h
@@ -46,14 +46,14 @@ namespace BitTorrent
 
     struct TorrentCreatorParams
     {
-        bool isPrivate;
+        bool isPrivate = false;
 #ifdef QBT_USES_LIBTORRENT2
-        TorrentFormat torrentFormat;
+        TorrentFormat torrentFormat = TorrentFormat::Hybrid;
 #else
         bool isAlignmentOptimized;
         int paddedFileSizeLimit;
 #endif
-        int pieceSize;
+        int pieceSize = 0;
         Path inputPath;
         Path savePath;
         QString comment;
diff --git a/src/base/bittorrent/torrentimpl.h b/src/base/bittorrent/torrentimpl.h
index c0657ccf7..685944293 100644
--- a/src/base/bittorrent/torrentimpl.h
+++ b/src/base/bittorrent/torrentimpl.h
@@ -84,7 +84,7 @@ namespace BitTorrent
     struct FileErrorInfo
     {
         lt::error_code error;
-        lt::operation_t operation;
+        lt::operation_t operation = lt::operation_t::unknown;
     };
 
     class TorrentImpl final : public Torrent
diff --git a/src/base/http/requestparser.h b/src/base/http/requestparser.h
index 56ecc51e8..0cab0db0e 100644
--- a/src/base/http/requestparser.h
+++ b/src/base/http/requestparser.h
@@ -47,9 +47,9 @@ namespace Http
         struct ParseResult
         {
             // when `status != ParseStatus::OK`, `request` & `frameSize` are undefined
-            ParseStatus status;
+            ParseStatus status = ParseStatus::BadRequest;
             Request request;
-            long frameSize;  // http request frame size (bytes)
+            long frameSize = 0;  // http request frame size (bytes)
         };
 
         static ParseResult parse(const QByteArray &data);
diff --git a/src/base/http/types.h b/src/base/http/types.h
index 41b2b8bf5..fca20dc6c 100644
--- a/src/base/http/types.h
+++ b/src/base/http/types.h
@@ -79,10 +79,10 @@ namespace Http
     struct Environment
     {
         QHostAddress localAddress;
-        quint16 localPort;
+        quint16 localPort = 0;
 
         QHostAddress clientAddress;
-        quint16 clientPort;
+        quint16 clientPort = 0;
     };
 
     struct UploadedFile
diff --git a/src/base/logger.h b/src/base/logger.h
index 429335e36..39aa8afb1 100644
--- a/src/base/logger.h
+++ b/src/base/logger.h
@@ -51,17 +51,17 @@ namespace Log
 
     struct Msg
     {
-        int id;
-        MsgType type;
-        qint64 timestamp;
+        int id = -1;
+        MsgType type = ALL;
+        qint64 timestamp = -1;
         QString message;
     };
 
     struct Peer
     {
-        int id;
-        bool blocked;
-        qint64 timestamp;
+        int id = -1;
+        bool blocked = false;
+        qint64 timestamp = -1;
         QString ip;
         QString reason;
     };
diff --git a/src/base/net/dnsupdater.cpp b/src/base/net/dnsupdater.cpp
index 2339c6444..0d201adc3 100644
--- a/src/base/net/dnsupdater.cpp
+++ b/src/base/net/dnsupdater.cpp
@@ -44,8 +44,6 @@ const std::chrono::seconds IP_CHECK_INTERVAL = 30min;
 
 DNSUpdater::DNSUpdater(QObject *parent)
     : QObject(parent)
-    , m_state(OK)
-    , m_service(DNS::Service::None)
 {
     updateCredentials();
 
diff --git a/src/base/net/dnsupdater.h b/src/base/net/dnsupdater.h
index e7141b82f..b89ec0e61 100644
--- a/src/base/net/dnsupdater.h
+++ b/src/base/net/dnsupdater.h
@@ -74,9 +74,9 @@ namespace Net
         QHostAddress m_lastIP;
         QDateTime m_lastIPCheckTime;
         QTimer m_ipCheckTimer;
-        int m_state;
+        int m_state = OK;
         // Service creds
-        DNS::Service m_service;
+        DNS::Service m_service = DNS::Service::None;
         QString m_domain;
         QString m_username;
         QString m_password;
diff --git a/src/base/net/downloadmanager.h b/src/base/net/downloadmanager.h
index 19c2ce085..aeb2b4887 100644
--- a/src/base/net/downloadmanager.h
+++ b/src/base/net/downloadmanager.h
@@ -103,7 +103,7 @@ namespace Net
     struct DownloadResult
     {
         QString url;
-        DownloadStatus status;
+        DownloadStatus status = DownloadStatus::Failed;
         QString errorString;
         QByteArray data;
         Path filePath;
diff --git a/src/base/search/searchhandler.h b/src/base/search/searchhandler.h
index bda41fe89..b11a24de7 100644
--- a/src/base/search/searchhandler.h
+++ b/src/base/search/searchhandler.h
@@ -42,9 +42,9 @@ struct SearchResult
 {
     QString fileName;
     QString fileUrl;
-    qlonglong fileSize;
-    qlonglong nbSeeders;
-    qlonglong nbLeechers;
+    qlonglong fileSize = 0;
+    qlonglong nbSeeders = 0;
+    qlonglong nbLeechers = 0;
     QString siteUrl;
     QString descrLink;
 };
diff --git a/src/base/search/searchpluginmanager.h b/src/base/search/searchpluginmanager.h
index 0425f9439..fcba073f0 100644
--- a/src/base/search/searchpluginmanager.h
+++ b/src/base/search/searchpluginmanager.h
@@ -52,7 +52,7 @@ struct PluginInfo
     QString url;
     QStringList supportedCategories;
     Path iconPath;
-    bool enabled;
+    bool enabled = false;
 };
 
 class SearchDownloadHandler;
diff --git a/src/gui/properties/speedplotview.h b/src/gui/properties/speedplotview.h
index 7ef62f043..04b6dc28a 100644
--- a/src/gui/properties/speedplotview.h
+++ b/src/gui/properties/speedplotview.h
@@ -139,5 +139,5 @@ private:
     Averager *m_currentAverager {&m_averager5Min};
 
     QMap<GraphID, GraphProperties> m_properties;
-    milliseconds m_currentMaxDuration;
+    milliseconds m_currentMaxDuration {0};
 };
diff --git a/src/gui/search/searchsortmodel.cpp b/src/gui/search/searchsortmodel.cpp
index 671b594eb..becf1ea72 100644
--- a/src/gui/search/searchsortmodel.cpp
+++ b/src/gui/search/searchsortmodel.cpp
@@ -32,13 +32,6 @@
 
 SearchSortModel::SearchSortModel(QObject *parent)
     : base(parent)
-    , m_isNameFilterEnabled(false)
-    , m_minSeeds(0)
-    , m_maxSeeds(-1)
-    , m_minLeeches(0)
-    , m_maxLeeches(-1)
-    , m_minSize(0)
-    , m_maxSize(-1)
 {
     setSortRole(UnderlyingDataRole);
     setFilterRole(UnderlyingDataRole);
diff --git a/src/gui/search/searchsortmodel.h b/src/gui/search/searchsortmodel.h
index c5cf785bd..32f239d34 100644
--- a/src/gui/search/searchsortmodel.h
+++ b/src/gui/search/searchsortmodel.h
@@ -90,12 +90,12 @@ protected:
     bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const override;
 
 private:
-    bool m_isNameFilterEnabled;
+    bool m_isNameFilterEnabled = false;
     QString m_searchTerm;
     QStringList m_searchTermWords;
-    int m_minSeeds, m_maxSeeds;
-    int m_minLeeches, m_maxLeeches;
-    qint64 m_minSize, m_maxSize;
+    int m_minSeeds = 0, m_maxSeeds = -1;
+    int m_minLeeches = 0, m_maxLeeches = -1;
+    qint64 m_minSize = 0, m_maxSize = -1;
 
     Utils::Compare::NaturalLessThan<Qt::CaseInsensitive> m_naturalLessThan;
 };
diff --git a/src/gui/torrenttagsdialog.h b/src/gui/torrenttagsdialog.h
index b8cf9edde..c95e26337 100644
--- a/src/gui/torrenttagsdialog.h
+++ b/src/gui/torrenttagsdialog.h
@@ -52,6 +52,6 @@ public:
 private:
     void addNewTag();
 
-    Ui::TorrentTagsDialog *m_ui;
+    Ui::TorrentTagsDialog *m_ui = nullptr;
     SettingValue<QSize> m_storeDialogSize;
 };
diff --git a/src/gui/transferlistfilters/categoryfiltermodel.h b/src/gui/transferlistfilters/categoryfiltermodel.h
index 1ba799f09..9576f094a 100644
--- a/src/gui/transferlistfilters/categoryfiltermodel.h
+++ b/src/gui/transferlistfilters/categoryfiltermodel.h
@@ -72,6 +72,6 @@ private:
     QModelIndex index(CategoryModelItem *item) const;
     CategoryModelItem *findItem(const QString &fullName) const;
 
-    bool m_isSubcategoriesEnabled;
+    bool m_isSubcategoriesEnabled = false;
     CategoryModelItem *m_rootItem = nullptr;
 };
diff --git a/src/gui/tristatewidget.cpp b/src/gui/tristatewidget.cpp
index bc4cb0db9..2219dcb84 100644
--- a/src/gui/tristatewidget.cpp
+++ b/src/gui/tristatewidget.cpp
@@ -38,8 +38,6 @@
 
 TriStateWidget::TriStateWidget(const QString &text, QWidget *parent)
     : QWidget {parent}
-    , m_closeOnInteraction {true}
-    , m_checkState {Qt::Unchecked}
     , m_text {text}
 {
     setMouseTracking(true);  // for visual effects via mouse navigation
diff --git a/src/gui/tristatewidget.h b/src/gui/tristatewidget.h
index b65a3b541..4b5eba75b 100644
--- a/src/gui/tristatewidget.h
+++ b/src/gui/tristatewidget.h
@@ -55,7 +55,7 @@ private:
 
     void toggleCheckState();
 
-    bool m_closeOnInteraction;
-    Qt::CheckState m_checkState;
+    bool m_closeOnInteraction = true;
+    Qt::CheckState m_checkState = Qt::Unchecked;
     const QString m_text;
 };
diff --git a/src/gui/uithemedialog.h b/src/gui/uithemedialog.h
index 3d137c864..ffea740d1 100644
--- a/src/gui/uithemedialog.h
+++ b/src/gui/uithemedialog.h
@@ -60,7 +60,7 @@ private:
     bool storeColors();
     bool storeIcons();
 
-    Ui::UIThemeDialog *m_ui;
+    Ui::UIThemeDialog *m_ui = nullptr;
     SettingValue<QSize> m_storeDialogSize;
 
     DefaultThemeSource m_defaultThemeSource;
diff --git a/src/webui/webapplication.h b/src/webui/webapplication.h
index 51443a2ad..150aa3e84 100644
--- a/src/webui/webapplication.h
+++ b/src/webui/webapplication.h
@@ -222,21 +222,21 @@ private:
     bool m_translationFileLoaded = false;
 
     AuthController *m_authController = nullptr;
-    bool m_isLocalAuthEnabled;
-    bool m_isAuthSubnetWhitelistEnabled;
+    bool m_isLocalAuthEnabled = false;
+    bool m_isAuthSubnetWhitelistEnabled = false;
     QVector<Utils::Net::Subnet> m_authSubnetWhitelist;
-    int m_sessionTimeout;
+    int m_sessionTimeout = 0;
     QString m_sessionCookieName;
 
     // security related
     QStringList m_domainList;
-    bool m_isCSRFProtectionEnabled;
-    bool m_isSecureCookieEnabled;
-    bool m_isHostHeaderValidationEnabled;
-    bool m_isHttpsEnabled;
+    bool m_isCSRFProtectionEnabled = true;
+    bool m_isSecureCookieEnabled = true;
+    bool m_isHostHeaderValidationEnabled = true;
+    bool m_isHttpsEnabled = false;
 
     // Reverse proxy
-    bool m_isReverseProxySupportEnabled;
+    bool m_isReverseProxySupportEnabled = false;
     QVector<Utils::Net::Subnet> m_trustedReverseProxyList;
     QHostAddress m_clientAddress;