diff --git a/panels/dock/taskmanager/abstractwindowmonitor.cpp b/panels/dock/taskmanager/abstractwindowmonitor.cpp
index 7f526a05a..ae07623d3 100644
--- a/panels/dock/taskmanager/abstractwindowmonitor.cpp
+++ b/panels/dock/taskmanager/abstractwindowmonitor.cpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2024 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2024 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -76,10 +76,15 @@ void AbstractWindowMonitor::requestWindowsView(const QModelIndexList &indexes) c
 
 QVariant AbstractWindowMonitor::data(const QModelIndex &index, int role) const
 {
+    if (!index.isValid())
+        return QVariant();
+
     auto pos = index.row();
-    if (pos >= m_trackedWindows.size())
+    if (pos < 0 || pos >= m_trackedWindows.size())
+        return QVariant();
+    auto window = m_trackedWindows.value(pos, nullptr);
+    if (!window)
         return QVariant();
-    auto window = m_trackedWindows[pos];
 
     switch (role) {
     case TaskManager::WinIdRole:
diff --git a/panels/dock/taskmanager/rolecombinemodel.cpp b/panels/dock/taskmanager/rolecombinemodel.cpp
index 23b59eebf..bb5345180 100644
--- a/panels/dock/taskmanager/rolecombinemodel.cpp
+++ b/panels/dock/taskmanager/rolecombinemodel.cpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2024 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2024 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -342,6 +342,10 @@ int RoleCombineModel::columnCount(const QModelIndex &parent) const
 
 QVariant RoleCombineModel::data(const QModelIndex &index, int role) const
 {
+    if (!index.isValid() || !sourceModel()) {
+        return QVariant();
+    }
+
     if (m_minorRolesMap.contains(role)) {
         auto majorKey = qMakePair(index.row(), index.column());
         auto mapping = m_indexMap.value(majorKey, qMakePair(-1, -1));
@@ -355,7 +359,12 @@ QVariant RoleCombineModel::data(const QModelIndex &index, int role) const
 
         return m_minor->data(m_minor->index(row, column), m_minorRolesMap[role]);
     } else {
-        return sourceModel()->data(sourceModel()->index(index.row(), index.column()), role);
+        auto sourceIndex = sourceModel()->index(index.row(), index.column());
+        if (!sourceIndex.isValid()) {
+            return QVariant();
+        }
+
+        return sourceModel()->data(sourceIndex, role);
     }
 }
 
diff --git a/panels/dock/taskmanager/taskmanager.cpp b/panels/dock/taskmanager/taskmanager.cpp
index 3ad7f76b8..0c64335f5 100644
--- a/panels/dock/taskmanager/taskmanager.cpp
+++ b/panels/dock/taskmanager/taskmanager.cpp
@@ -327,8 +327,11 @@ void TaskManager::handleWindowAdded(QPointer<AbstractWindow> window)
 
     // TODO: remove below code and use use model replaced.
     QModelIndexList res;
-    if (m_activeAppModel) {
-        res = m_activeAppModel->match(m_activeAppModel->index(0, 0), TaskManager::WinIdRole, window->id());
+    if (m_activeAppModel && m_activeAppModel->rowCount() > 0) {
+        auto startIndex = m_activeAppModel->index(0, 0);
+        if (startIndex.isValid()) {
+            res = m_activeAppModel->match(startIndex, TaskManager::WinIdRole, window->id());
+        }
     }
 
     QSharedPointer<DesktopfileAbstractParser> desktopfile = nullptr;