diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj
index 6a269f5..7c4bfd3 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj
@@ -157,6 +157,7 @@
     <ClInclude Include="core\patterns\Observer.h" />
     <ClInclude Include="core\patterns\Subject.h" />
     <ClInclude Include="datastores\DataStore.h" />
+    <ClInclude Include="datastores\DataStoreLockGuard.h" />
     <ClInclude Include="datastores\sharedmemory\FileHeader.h" />
     <ClInclude Include="datastores\sharedmemory\MappingInfo.h" />
     <ClInclude Include="datastores\sharedmemory\RecordState.h" />
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters
index 7e74b19..94301c4 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters
@@ -278,5 +278,8 @@
     <ClInclude Include="datastores\sharedmemory\SharedMemory.h">
       <Filter>Header Files\DataStores\SharedMemory</Filter>
     </ClInclude>
+    <ClInclude Include="datastores\DataStoreLockGuard.h">
+      <Filter>Header Files\DataStores</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStore.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStore.cpp
index 1cade32..f430184 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStore.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStore.cpp
@@ -228,6 +228,22 @@ Returns:
 */
 util::Map<std::string, TrackedRecord<User>>& DataStore::getUsers()
 {
+    auto users = loadRecords<User, SerializedUser>(m_users);
+    refreshCache(m_userCache, users);
+    auto& notifications = getNotifications();
+    int numberOfNotifications = m_notificationCache.getSize();
+    for (int index = 0; index < numberOfNotifications; index++)
+    {
+        Notification* notification = notifications.getValueAt(index).data;
+        const std::string& recipientUserId = notification->getRecipientUserId();
+        int userIndex = m_userCache.find(recipientUserId);
+        if (userIndex == -1)
+        {
+            throw std::runtime_error("Invalid recipient user ID");
+        }
+        User* user = m_userCache.getValueAt(userIndex).data;
+        user->addNotification(notification);
+    }
     return m_userCache;
 }
 
@@ -371,6 +387,8 @@ Returns:
 */
 void DataStore::saveUsers()
 {
+    saveRecords<User, SerializedUser>(m_users, m_userCache);
+    saveNotifications();
 }
 
 /*
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStoreLockGuard.h b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStoreLockGuard.h
new file mode 100644
index 0000000..2e04eb0
--- /dev/null
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStoreLockGuard.h
@@ -0,0 +1,28 @@
+/*
+File: DataStoreLockGuard.h
+Description: Defines the DataStoreLockGuard class used to manage DataStore
+             locking and unlocking automatically within a scope.
+Author: Trenser
+Date: 12-June-2026
+*/
+
+#pragma once
+#include "DataStore.h"
+
+class DataStoreLockGuard
+{
+public:
+    explicit DataStoreLockGuard(DataStore& dataStore)
+        : m_dataStore(dataStore)
+    {
+        m_dataStore.lockDataStore();
+    }
+    ~DataStoreLockGuard()
+    {
+        m_dataStore.unlockDataStore();
+    }
+    DataStoreLockGuard(const DataStoreLockGuard&) = delete;
+    DataStoreLockGuard& operator=(const DataStoreLockGuard&) = delete;
+private:
+    DataStore& m_dataStore;
+};
\ No newline at end of file
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/AuthenticationManagementService.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/AuthenticationManagementService.cpp
index dc3a94c..27be89f 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/AuthenticationManagementService.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/AuthenticationManagementService.cpp
@@ -10,6 +10,8 @@ Date:19-May-2026
 #include <stdexcept>
 #include "AuthenticationManagementService.h"
 #include "User.h"
+#include "Utility.h"
+#include "DataStoreLockGuard.h"
 
 User* AuthenticationManagementService::m_authenticatedUser = nullptr;
 
@@ -24,11 +26,12 @@ Return type: bool - true if login successful, false otherwise
 */
 bool AuthenticationManagementService::login(const std::string& username, const std::string& password)
 {
-	util::Map<std::string, User*> users = m_dataStore.getUsers();
-	int usersMapSize = users.getSize();
-	for (int index = 0; index < usersMapSize; index++)
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUserMap = m_dataStore.getUsers();
+	int trackedUserMapSize = trackedUserMap.getSize();
+	for (int index = 0; index < trackedUserMapSize; index++)
 	{
-		User* user = users.getValueAt(index);
+		User* user = trackedUserMap.getValueAt(index).data;
 		if (username == user->getUserName())
 		{
 			if (password == user->getPassword())
@@ -74,9 +77,18 @@ Return type: void
 */
 void AuthenticationManagementService::changePassword(const std::string& newPassword)
 {
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	int index = trackedUsersMap.find(m_authenticatedUser->getId());
+	if (index == -1)
+	{
+		throw std::runtime_error("User does not exist!\n");
+	}
 	if (m_authenticatedUser == nullptr)
 	{
 		throw std::runtime_error("There is no user currently logged in!");
 	}
 	m_authenticatedUser->setPassword(newPassword);
+	trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
+	m_dataStore.saveUsers();
 }