diff --git a/src/manager.c b/src/manager.c
index b832df7..37f541d 100644
--- a/src/manager.c
+++ b/src/manager.c
@@ -8,7 +8,7 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 
-#define PROCESS_MOM_TO 200 // in ms
+#define PROCESS_MOM_TO 50 // in ms
 
 #define DBUS_SERVER_NAME "dev.iohub.diya.SessionManager"
 #define DBUS_SERVER_PATH "/dev/iohub/diya/SessionManager"
@@ -256,14 +256,15 @@ static void start_user_session(SessionManager *self)
     if (self->login_session_pid > 0)
     {
         int status;
-        pid_t pid = waitpid(self->login_session_pid, &status, WNOHANG);
-        if(pid < 0)
+        pid_t pid = waitpid(self->login_session_pid, &status, 0);
+        if(pid <= 0)
         {
             g_warning("start_user_session: login session is still running or waitpid error: %s. Force kill it", strerror(errno));
             // try to kill it
             (void)kill(self->login_session_pid, SIGKILL);
+            pid = waitpid(self->login_session_pid, &status, 0);
         }
-        g_debug("start_user_session: login session is exited");
+        g_debug("start_user_session: login session is exited: %d", pid);
         self->login_session_pid = 0;
     }
     if(self->session_pid > 0)
@@ -499,6 +500,7 @@ static gboolean processes_monitor(gpointer user_data)
                 g_critical("session waitpid error: %s", strerror(errno));
                 // try to kill it
                 (void)kill(self->session_pid, SIGKILL);
+                (void)waitpid(self->session_pid, &status, 0);
                 self->session_pid = -1;
             }
             if(pid == 0)
@@ -515,6 +517,7 @@ static gboolean processes_monitor(gpointer user_data)
                 g_critical("login session waitpid error: %s", strerror(errno));
                 // try to kill it
                 (void)kill(self->login_session_pid, SIGKILL);
+                (void)waitpid(self->login_session_pid, &status, 0);
                 self->login_session_pid = -1;
             }
             if(pid == 0)