diff --git a/api/dbus/org.desktopspec.ApplicationManager1.Instance.xml b/api/dbus/org.desktopspec.ApplicationManager1.Instance.xml
index bfb7d66..d8eadff 100644
--- a/api/dbus/org.desktopspec.ApplicationManager1.Instance.xml
+++ b/api/dbus/org.desktopspec.ApplicationManager1.Instance.xml
@@ -25,5 +25,21 @@
                        if this instance is not managed by systemd."
             />
         </property>
+
+        <property name="Launcher" type="s" access="read">
+            <annotation
+                name="org.freedesktop.DBus.Description"
+                value="This property indicates which Application
+                       launcher started this instance." 
+            />
+        </property>
+
+        <property name="Orphaned" type="b" access="read">
+            <annotation
+                name="org.freedesktop.DBus.Description"
+                value="This property indicates that the application 
+                       to which the instance belonged has been removed."
+            />
+        </property>
     </interface>
 </node>
diff --git a/src/cgroupsidentifier.cpp b/src/cgroupsidentifier.cpp
index ab434ff..61d710e 100644
--- a/src/cgroupsidentifier.cpp
+++ b/src/cgroupsidentifier.cpp
@@ -19,7 +19,7 @@ IdentifyRet CGroupsIdentifier::Identify(pid_t pid)
 
     auto UnitStr = parseCGroupsPath(AppCgroupFile);
 
-    auto [appId, InstanceId] = processUnitName(UnitStr);
+    auto [appId, launcher, InstanceId] = processUnitName(UnitStr);
     return {std::move(appId), std::move(InstanceId)};
 }
 
diff --git a/src/dbus/applicationmanager1service.cpp b/src/dbus/applicationmanager1service.cpp
index 1d5b9cc..7eb1f09 100644
--- a/src/dbus/applicationmanager1service.cpp
+++ b/src/dbus/applicationmanager1service.cpp
@@ -103,9 +103,11 @@ void ApplicationManager1Service::addInstanceToApplication(const QString &unitNam
         return;
     }
 
-    auto pair = processUnitName(unitName);
-    auto appId = pair.first;
-    auto instanceId = pair.second;
+    auto info = processUnitName(unitName);
+    auto appId = std::move(info.applicationID);
+    auto launcher = std::move(info.Launcher);
+    auto instanceId = std::move(info.instanceID);
+
     if (appId.isEmpty()) {
         return;
     }
@@ -132,7 +134,7 @@ void ApplicationManager1Service::addInstanceToApplication(const QString &unitNam
 
     const auto &applicationPath = (*appIt)->applicationPath().path();
 
-    if (!(*appIt)->addOneInstance(instanceId, applicationPath, systemdUnitPath.path())) [[likely]] {
+    if (!(*appIt)->addOneInstance(instanceId, applicationPath, systemdUnitPath.path(), launcher)) [[likely]] {
         qCritical() << "add Instance failed:" << applicationPath << unitName << systemdUnitPath.path();
     }
 }
@@ -143,9 +145,11 @@ void ApplicationManager1Service::removeInstanceFromApplication(const QString &un
         return;
     }
 
-    auto pair = processUnitName(unitName);
-    auto appId = pair.first;
-    auto instanceId = pair.second;
+    auto info = processUnitName(unitName);
+    auto appId = std::move(info.applicationID);
+    auto launcher = std::move(info.Launcher);
+    auto instanceId = std::move(info.instanceID);
+
     if (appId.isEmpty()) {
         return;
     }
@@ -163,12 +167,17 @@ void ApplicationManager1Service::removeInstanceFromApplication(const QString &un
 
     auto instanceIt =
         std::find_if(appIns.cbegin(), appIns.cend(), [&systemdUnitPath](const QSharedPointer<InstanceService> &value) {
-            return value->systemdUnitPath() == systemdUnitPath;
+            return value->property("SystemdUnitPath") == systemdUnitPath;
         });
 
     if (instanceIt != appIns.cend()) [[likely]] {
         (*appIt)->removeOneInstance(instanceIt.key());
+        return;
     }
+
+    orphanedInstances->removeIf([&systemdUnitPath](const QSharedPointer<InstanceService> &ptr) {
+        return (ptr->property("SystemdUnitPath").value<QDBusObjectPath>() == systemdUnitPath);
+    });
 }
 
 void ApplicationManager1Service::scanApplications() noexcept
@@ -357,28 +366,28 @@ QString ApplicationManager1Service::Identify(const QDBusUnixFileDescriptor &pidf
 }
 
 void ApplicationManager1Service::updateApplication(const QSharedPointer<ApplicationService> &destApp,
-                                                   const DesktopFile &desktopFile) noexcept
+                                                   DesktopFile desktopFile) noexcept
 {
     // TODO: add propertyChanged
     if (auto app = m_applicationList.find(destApp->applicationPath()); app == m_applicationList.cend()) {
         return;
     }
 
-    auto timeInfo = getFileTimeInfo(QFileInfo{desktopFile.sourceFileRef()});
+    auto *newEntry = new (std::nothrow) DesktopEntry{};
+    if (newEntry == nullptr) {
+        qCritical() << "new DesktopEntry failed.";
+        return;
+    }
 
-    if (destApp->desktopFileSource().modified(timeInfo.mtime)) {
-        auto *newEntry = new (std::nothrow) DesktopEntry{};
-        if (newEntry == nullptr) {
-            qCritical() << "new DesktopEntry failed.";
-            return;
-        }
+    auto err = newEntry->parse(desktopFile);
+    if (err != DesktopErrorCode::NoError) {
+        qWarning() << "update desktop file failed:" << err << ", content wouldn't change.";
+        return;
+    }
 
-        auto err = newEntry->parse(destApp->desktopFileSource());
-        if (err != DesktopErrorCode::NoError) {
-            qWarning() << "update desktop file failed:" << err << ", content wouldn't change.";
-            return;
-        }
+    if (destApp->m_entry != newEntry) {
         destApp->resetEntry(newEntry);
+        destApp->m_desktopSource = std::move(desktopFile);
     }
 }
 
@@ -407,9 +416,9 @@ void ApplicationManager1Service::ReloadApplications()
             return false;
         }
 
-        if (destApp != m_applicationList.cend()) {
+        if (destApp != m_applicationList.cend() and apps.contains(destApp.key())) {
             apps.removeOne(destApp.key());
-            updateApplication(destApp.value(), file);
+            updateApplication(destApp.value(), std::move(file));
             return false;
         }
 
diff --git a/src/dbus/applicationmanager1service.h b/src/dbus/applicationmanager1service.h
index cfe8fcb..18cb369 100644
--- a/src/dbus/applicationmanager1service.h
+++ b/src/dbus/applicationmanager1service.h
@@ -39,7 +39,7 @@ public:
     void removeOneApplication(const QDBusObjectPath &application) noexcept;
     void removeAllApplication() noexcept;
 
-    void updateApplication(const QSharedPointer<ApplicationService> &destApp, const DesktopFile &desktopFile) noexcept;
+    void updateApplication(const QSharedPointer<ApplicationService> &destApp, DesktopFile desktopFile) noexcept;
 
     JobManager1Service &jobManager() noexcept { return *m_jobManager; }
 
diff --git a/src/dbus/applicationservice.cpp b/src/dbus/applicationservice.cpp
index c467cc0..bad298d 100644
--- a/src/dbus/applicationservice.cpp
+++ b/src/dbus/applicationservice.cpp
@@ -34,10 +34,8 @@ ApplicationService::ApplicationService(DesktopFile source,
 ApplicationService::~ApplicationService()
 {
     for (auto &instance : m_Instances.values()) {
-        instance->m_Application = QDBusObjectPath{"/"};
-        auto *ptr = instance.get();
-        instance.reset(nullptr);
-        ptr->setParent(qApp);  // detach all instances to qApp
+        orphanedInstances->append(instance);
+        instance->m_orphaned = true;
     }
 }
 
@@ -465,9 +463,12 @@ QList<QDBusObjectPath> ApplicationService::instances() const noexcept
     return m_Instances.keys();
 }
 
-bool ApplicationService::addOneInstance(const QString &instanceId, const QString &application, const QString &systemdUnitPath)
+bool ApplicationService::addOneInstance(const QString &instanceId,
+                                        const QString &application,
+                                        const QString &systemdUnitPath,
+                                        const QString &launcher)
 {
-    auto *service = new InstanceService{instanceId, application, systemdUnitPath};
+    auto *service = new InstanceService{instanceId, application, systemdUnitPath, launcher};
     auto *adaptor = new InstanceAdaptor(service);
     QString objectPath{m_applicationPath.path() + "/" + instanceId};
 
diff --git a/src/dbus/applicationservice.h b/src/dbus/applicationservice.h
index f08fa5f..98239ac 100644
--- a/src/dbus/applicationservice.h
+++ b/src/dbus/applicationservice.h
@@ -86,7 +86,10 @@ public:
     [[nodiscard]] const QString &getLauncher() const noexcept { return m_launcher; }
     void setLauncher(const QString &launcher) noexcept { m_launcher = launcher; }
 
-    bool addOneInstance(const QString &instanceId, const QString &application, const QString &systemdUnitPath);
+    bool addOneInstance(const QString &instanceId,
+                        const QString &application,
+                        const QString &systemdUnitPath,
+                        const QString &launcher);
     void recoverInstances(const QList<QDBusObjectPath> &instanceList) noexcept;
     void removeOneInstance(const QDBusObjectPath &instance) noexcept;
     void removeAllInstance() noexcept;
diff --git a/src/dbus/instanceservice.cpp b/src/dbus/instanceservice.cpp
index 0032272..11d14ae 100644
--- a/src/dbus/instanceservice.cpp
+++ b/src/dbus/instanceservice.cpp
@@ -3,22 +3,14 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 
 #include "dbus/instanceservice.h"
+#include <QCoreApplication>
 
-InstanceService::InstanceService(QString instanceId, QString application, QString systemdUnitPath)
-    : m_instanceId(std::move(instanceId))
+InstanceService::InstanceService(QString instanceId, QString application, QString systemdUnitPath, QString launcher)
+    : m_Launcher(std::move(launcher))
+    , m_instanceId(std::move(instanceId))
     , m_Application(std::move(application))
     , m_SystemdUnitPath(std::move(systemdUnitPath))
 {
 }
 
 InstanceService::~InstanceService() = default;
-
-QDBusObjectPath InstanceService::application() const
-{
-    return m_Application;
-}
-
-QDBusObjectPath InstanceService::systemdUnitPath() const
-{
-    return m_SystemdUnitPath;
-}
diff --git a/src/dbus/instanceservice.h b/src/dbus/instanceservice.h
index bd9aa39..0f18ae0 100644
--- a/src/dbus/instanceservice.h
+++ b/src/dbus/instanceservice.h
@@ -18,20 +18,23 @@ public:
     InstanceService &operator=(const InstanceService &) = delete;
     InstanceService &operator=(InstanceService &&) = delete;
 
-    Q_PROPERTY(QDBusObjectPath Application READ application)
-    [[nodiscard]] QDBusObjectPath application() const;
-
-    Q_PROPERTY(QDBusObjectPath SystemdUnitPath READ systemdUnitPath)
-    [[nodiscard]] QDBusObjectPath systemdUnitPath() const;
+    Q_PROPERTY(QDBusObjectPath Application MEMBER m_Application)
+    Q_PROPERTY(QDBusObjectPath SystemdUnitPath MEMBER m_SystemdUnitPath)
+    Q_PROPERTY(QString Launcher MEMBER m_Launcher)
+    Q_PROPERTY(bool Orphaned MEMBER m_orphaned)
 
     [[nodiscard]] const QString &instanceId() const noexcept { return m_instanceId; }
 
 private:
     friend class ApplicationService;
-    InstanceService(QString instanceId, QString application, QString systemdUnitPath);
+    InstanceService(QString instanceId, QString application, QString systemdUnitPath, QString launcher);
+    bool m_orphaned{false};
+    QString m_Launcher;
     QString m_instanceId;
     QDBusObjectPath m_Application;
     QDBusObjectPath m_SystemdUnitPath;
 };
 
+Q_GLOBAL_STATIC(QList<QSharedPointer<InstanceService>>, orphanedInstances)
+
 #endif
diff --git a/src/desktopentry.cpp b/src/desktopentry.cpp
index 47b4028..b79405f 100644
--- a/src/desktopentry.cpp
+++ b/src/desktopentry.cpp
@@ -369,7 +369,7 @@ bool DesktopFile::modified(qint64 time) const noexcept
     return time != m_mtime;
 }
 
-DesktopErrorCode DesktopEntry::parse(DesktopFile &file) noexcept
+DesktopErrorCode DesktopEntry::parse(const DesktopFile &file) noexcept
 {
     DesktopFileGuard guard{file};
 
@@ -538,6 +538,24 @@ float DesktopEntry::Value::toNumeric(bool &ok) const noexcept
     return v.toFloat(&ok);
 }
 
+bool operator==(const DesktopEntry &lhs, const DesktopEntry &rhs)
+{
+    if (lhs.m_parsed != rhs.m_parsed) {
+        return false;
+    }
+
+    if (lhs.m_entryMap != rhs.m_entryMap) {
+        return false;
+    }
+
+    return true;
+}
+
+bool operator!=(const DesktopEntry &lhs, const DesktopEntry &rhs)
+{
+    return !(lhs == rhs);
+}
+
 QDebug operator<<(QDebug debug, const DesktopEntry::Value &v)
 {
     QDebugStateSaver saver{debug};
diff --git a/src/desktopentry.h b/src/desktopentry.h
index e3827e2..be6d16c 100644
--- a/src/desktopentry.h
+++ b/src/desktopentry.h
@@ -80,7 +80,7 @@ struct DesktopFileGuard
     DesktopFileGuard &operator=(const DesktopFileGuard &) = delete;
     DesktopFileGuard &operator=(DesktopFileGuard &&) = delete;
 
-    explicit DesktopFileGuard(DesktopFile &file)
+    explicit DesktopFileGuard(const DesktopFile &file)
         : fileRef(file)
     {
     }
@@ -107,7 +107,7 @@ struct DesktopFileGuard
     }
 
 private:
-    DesktopFile &fileRef;
+    const DesktopFile &fileRef;
 };
 
 class DesktopEntry
@@ -135,11 +135,14 @@ public:
     DesktopEntry &operator=(DesktopEntry &&) = default;
 
     ~DesktopEntry() = default;
-    [[nodiscard]] DesktopErrorCode parse(DesktopFile &file) noexcept;
+    [[nodiscard]] DesktopErrorCode parse(const DesktopFile &file) noexcept;
     [[nodiscard]] DesktopErrorCode parse(QTextStream &stream) noexcept;
     [[nodiscard]] std::optional<QMap<QString, Value>> group(const QString &key) const noexcept;
     [[nodiscard]] std::optional<Value> value(const QString &key, const QString &valueKey) const noexcept;
 
+    friend bool operator==(const DesktopEntry &lhs, const DesktopEntry &rhs);
+    friend bool operator!=(const DesktopEntry &lhs, const DesktopEntry &rhs);
+
 private:
     [[nodiscard]] bool checkMainEntryValidation() const noexcept;
     QMap<QString, QMap<QString, Value>> m_entryMap;
@@ -150,4 +153,8 @@ QDebug operator<<(QDebug debug, const DesktopEntry::Value &v);
 
 QDebug operator<<(QDebug debug, const DesktopErrorCode &v);
 
+bool operator==(const DesktopEntry &lhs, const DesktopEntry &rhs);
+
+bool operator!=(const DesktopEntry &lhs, const DesktopEntry &rhs);
+
 #endif
diff --git a/src/global.h b/src/global.h
index 1f20817..7514dfa 100644
--- a/src/global.h
+++ b/src/global.h
@@ -233,11 +233,13 @@ inline QString getDBusInterface(const QMetaType &meta)
     if (name == "APPObjectManagerAdaptor" or name == "AMObjectManagerAdaptor") {
         return ObjectManagerInterface;
     }
-    // const auto *infoObject = meta.metaObject();
-    // if (auto infoIndex = infoObject->indexOfClassInfo("D-Bus Interface"); infoIndex != -1) {
-    //     return infoObject->classInfo(infoIndex).value();
-    // }
-    qWarning() << "couldn't found interface:" << name;
+
+    if (name == "ApplicationManager1Service")
+        // const auto *infoObject = meta.metaObject();
+        // if (auto infoIndex = infoObject->indexOfClassInfo("D-Bus Interface"); infoIndex != -1) {
+        //     return infoObject->classInfo(infoIndex).value();
+        // }
+        qWarning() << "couldn't found interface:" << name;
     return "";
 }
 
@@ -425,31 +427,48 @@ inline bool isApplication(const QDBusObjectPath &path)
     return path.path().split('/').last().startsWith("app");
 }
 
-inline QPair<QString, QString> processUnitName(const QString &unitName)
+struct unitInfo
+{
+    QString applicationID;
+    QString Launcher;
+    QString instanceID;
+};
+
+inline unitInfo processUnitName(const QString &unitName)
 {
     QString instanceId;
+    QString launcher;
     QString applicationId;
 
-    if (unitName.endsWith(".service")) {
-        auto lastDotIndex = unitName.lastIndexOf('.');
-        auto app = unitName.sliced(0, lastDotIndex);  // remove suffix
+    decltype(auto) appPrefix = u8"app-";
+    auto unit = unitName.sliced(sizeof(appPrefix) - 1);
+
+    if (unit.endsWith(".service")) {
+        auto lastDotIndex = unit.lastIndexOf('.');
+        auto app = unit.sliced(0, lastDotIndex);  // remove suffix
 
         if (app.contains('@')) {
             auto atIndex = app.indexOf('@');
             instanceId = app.sliced(atIndex + 1);
             app.remove(atIndex, instanceId.length() + 1);
         }
-
-        applicationId = app.split('-').last();  // drop launcher if it exists.
-    } else if (unitName.endsWith(".scope")) {
-        auto lastDotIndex = unitName.lastIndexOf('.');
-        auto app = unitName.sliced(0, lastDotIndex);
+        auto rest = app.split('-', Qt::SkipEmptyParts);
+        if (rest.size() == 2) {
+            launcher = rest.takeFirst();
+        }
+        applicationId = rest.takeFirst();
+    } else if (unit.endsWith(".scope")) {
+        auto lastDotIndex = unit.lastIndexOf('.');
+        auto app = unit.sliced(0, lastDotIndex);
 
         auto components = app.split('-');
         instanceId = components.takeLast();
         applicationId = components.takeLast();
+        if (!components.isEmpty()) {
+            launcher = components.takeLast();
+        }
     } else {
-        qDebug() << "it's not service or scope:" << unitName << "ignore";
+        qDebug() << "it's not service or scope:" << unit << "ignore";
         return {};
     }
 
@@ -457,7 +476,7 @@ inline QPair<QString, QString> processUnitName(const QString &unitName)
         instanceId = QUuid::createUuid().toString(QUuid::Id128);
     }
 
-    return qMakePair(unescapeApplicationId(applicationId), std::move(instanceId));
+    return {unescapeApplicationId(applicationId), std::move(launcher), std::move(instanceId)};
 }
 
 template <typename T>
diff --git a/src/propertiesForwarder.cpp b/src/propertiesForwarder.cpp
index b22ac94..54fdff9 100644
--- a/src/propertiesForwarder.cpp
+++ b/src/propertiesForwarder.cpp
@@ -42,12 +42,32 @@ void PropertiesForwarder::PropertyChanged()
         return;
     }
 
-    auto sig = mo->property(sigIndex + 1);
-    const auto *propName = sig.name();
-    auto value = sig.read(sender);
+    auto sig = mo->method(sigIndex);
+    auto signature = sig.methodSignature();
+
+    QByteArray propName;
+    for (auto i = mo->propertyOffset(); i < mo->propertyCount(); ++i) {
+        auto prop = mo->property(i);
+        if (!prop.hasNotifySignal()) {
+            continue;
+        }
+
+        if (prop.notifySignal().methodSignature() == signature) {
+            propName = prop.name();
+        }
+    }
+
+    if (propName.isEmpty()) {
+        qDebug() << "can't find corresponding property:" << signature;
+        return;
+    }
+
+    auto propIndex = mo->indexOfProperty(propName.constData());
+    auto prop = mo->property(propIndex);
+    auto value = prop.read(sender);
 
-    auto childs = sender->children();
     auto msg = QDBusMessage::createSignal(m_path, "org.freedesktop.DBus.Properties", "PropertiesChanged");
+
     msg << QString{ApplicationInterface};
     msg << QVariantMap{{QString{propName}, value}};
     msg << QStringList{};
diff --git a/src/systemdsignaldispatcher.cpp b/src/systemdsignaldispatcher.cpp
index 4c806cc..4308ef3 100644
--- a/src/systemdsignaldispatcher.cpp
+++ b/src/systemdsignaldispatcher.cpp
@@ -33,20 +33,18 @@ bool SystemdSignalDispatcher::connectToSignals() noexcept
 
 void SystemdSignalDispatcher::onUnitNew(QString unitName, QDBusObjectPath systemdUnitPath)
 {
-    decltype(auto) appPrefix = u8"app-";
-    if (!unitName.startsWith(appPrefix)) {
+    if (!unitName.startsWith("app-")) {
         return;
     }
 
-    emit SystemdUnitNew(unitName.sliced(sizeof(appPrefix) - 1), systemdUnitPath);
+    emit SystemdUnitNew(unitName, systemdUnitPath);
 }
 
 void SystemdSignalDispatcher::onUnitRemoved(QString unitName, QDBusObjectPath systemdUnitPath)
 {
-    decltype(auto) appPrefix = u8"app-";
-    if (!unitName.startsWith(appPrefix)) {
+    if (!unitName.startsWith("app-")) {
         return;
     }
 
-    emit SystemdUnitRemoved(unitName.sliced(sizeof(appPrefix) - 1), systemdUnitPath);
+    emit SystemdUnitRemoved(unitName, systemdUnitPath);
 }
diff --git a/tests/ut_applicationmanager.cpp b/tests/ut_applicationmanager.cpp
index 301c5e2..a68fbbb 100644
--- a/tests/ut_applicationmanager.cpp
+++ b/tests/ut_applicationmanager.cpp
@@ -38,8 +38,8 @@ public:
         auto ptr = std::make_unique<QFile>(QString{"/usr/share/applications/test-Application.desktop"});
         DesktopFile file{std::move(ptr), "test-Application", 0, 0};
         QSharedPointer<ApplicationService> app = QSharedPointer<ApplicationService>::create(std::move(file), nullptr, tmp);
-        QSharedPointer<InstanceService> instance =
-            QSharedPointer<InstanceService>::create(InstancePath.path().split('/').last(), ApplicationPath.path(), QString{"/"});
+        QSharedPointer<InstanceService> instance = QSharedPointer<InstanceService>::create(
+            InstancePath.path().split('/').last(), ApplicationPath.path(), QString{"/"}, QString{"DDE"});
         app->m_Instances.insert(InstancePath, instance);
         m_am->m_applicationList.insert(ApplicationPath, app);
     }