diff --git a/src/bin/base_gui.c b/src/bin/base_gui.c
index 25e743c..9c49e08 100644
--- a/src/bin/base_gui.c
+++ b/src/bin/base_gui.c
@@ -266,7 +266,7 @@ void
 base_gui_term(void)
 {
    base_data *bd = g_bd;
-   EINA_SAFETY_ON_NULL_RETURN(bd);
+   if (!bd) return;
 
    ecore_timer_del(bd->edc_navi_update_timer);
    file_browser_term();
diff --git a/src/bin/config_data.c b/src/bin/config_data.c
index 1c6836e..d1c0573 100644
--- a/src/bin/config_data.c
+++ b/src/bin/config_data.c
@@ -94,19 +94,22 @@ static void
 config_save(config_data *cd)
 {
    char buf[PATH_MAX];
+   const char *config_home = efreet_config_home_get();
+   if (!config_home) return;
 
    //Create config home directory if it doesn't exist.
-   if (!ecore_file_exists(efreet_config_home_get()))
+   if (!ecore_file_exists(config_home))
      {
-        Eina_Bool success = ecore_file_mkdir(efreet_config_home_get());
+        Eina_Bool success = ecore_file_mkdir(config_home);
         if (!success)
           {
-             EINA_LOG_ERR(_("Cannot create a config folder \"%s\""), efreet_config_home_get());
+             EINA_LOG_ERR(_("Cannot create a config folder \"%s\""),
+                          config_home);
              return;
           }
      }
 
-   snprintf(buf, sizeof(buf), "%s/enventor", efreet_config_home_get());
+   snprintf(buf, sizeof(buf), "%s/enventor", config_home);
 
    //Create enventor config folder if it doesn't exist.
    if (!ecore_file_exists(buf))
@@ -114,14 +117,14 @@ config_save(config_data *cd)
         Eina_Bool success = ecore_file_mkdir(buf);
         if (!success)
           {
-             EINA_LOG_ERR(_("Cannot create a config folder \"%s\""), buf);
+             EINA_LOG_ERR(_("Cannot create a enventor config folder \"%s\""),
+                          buf);
              return;
           }
      }
 
    //Save config file.
-   snprintf(buf, sizeof(buf), "%s/enventor/config.eet",
-            efreet_config_home_get());
+   snprintf(buf, sizeof(buf), "%s/enventor/config.eet", config_home);
    Eet_File *ef = eet_open(buf, EET_FILE_MODE_WRITE);
    if (!ef)
      {
@@ -395,6 +398,7 @@ void
 config_term(void)
 {
    config_data *cd = g_cd;
+   if (!cd) return;
 
    config_save(cd);
 
diff --git a/src/bin/file_mgr.c b/src/bin/file_mgr.c
index 3f6a911..0e9ab1b 100644
--- a/src/bin/file_mgr.c
+++ b/src/bin/file_mgr.c
@@ -228,7 +228,7 @@ void
 file_mgr_term(void)
 {
    file_mgr_data *fmd = g_fmd;
-   EINA_SAFETY_ON_NULL_RETURN(fmd);
+   if (!fmd) return;
 
    free(fmd);
 }
diff --git a/src/bin/live_edit.c b/src/bin/live_edit.c
index 7aa1a80..d3e9a20 100644
--- a/src/bin/live_edit.c
+++ b/src/bin/live_edit.c
@@ -2345,7 +2345,7 @@ void
 live_edit_term(void)
 {
    live_data *ld = g_ld;
-   EINA_SAFETY_ON_NULL_RETURN(ld);
+   if (!ld) return;
 
    live_edit_cancel(EINA_FALSE);
 
diff --git a/src/bin/main.c b/src/bin/main.c
index 71966e0..aad8b7a 100644
--- a/src/bin/main.c
+++ b/src/bin/main.c
@@ -13,6 +13,8 @@ typedef struct app_s
    Eina_Bool lazy_save : 1;
 } app_data;
 
+static Eina_Bool own_lock = EINA_FALSE;  //lock file owner?
+
 int main(int argc, char **argv);
 
 static void
@@ -912,6 +914,150 @@ keygrabber_init(app_data *ad)
    GRAB_ADD("Down", modifier);
 }
 
+static Eina_Bool
+enventor_lock_create(void)
+{
+   const char *config_home = efreet_config_home_get();
+
+   //Exception 1
+   //Create config home directory if it doesn't exist.
+   if (!config_home)
+     {
+        EINA_LOG_ERR("No config home directory?! = %s", config_home);
+        return EINA_TRUE;
+     }
+
+   //Exception 2
+   //Create config home directory if it doesn't exist.
+   if (!ecore_file_exists(config_home))
+     {
+        Eina_Bool success = ecore_file_mkdir(efreet_config_home_get());
+        if (!success)
+          {
+             EINA_LOG_ERR(_("Cannot create a config folder \"%s\""),
+                          config_home);
+             return EINA_TRUE;
+          }
+     }
+
+   char buf[PATH_MAX];
+   snprintf(buf, sizeof(buf), "%s/enventor", config_home);
+
+   //Exception 3
+   //Create enventor config folder if it doesn't exist.
+   if (!ecore_file_exists(buf))
+     {
+        Eina_Bool success = ecore_file_mkdir(buf);
+        if (!success)
+          {
+             EINA_LOG_ERR(_("Cannot create a enventor config folder \"%s\""),
+                          buf);
+             return EINA_TRUE;
+          }
+     }
+
+   snprintf(buf, sizeof(buf), "%s/enventor/"ENVENTOR_LOCK_FILE, config_home);
+
+   //Is there any other Enventor instance?
+   if (ecore_file_exists(buf))
+     {
+        fprintf(stdout, "Enventor program is already running!\n\n"
+                        "If you are really stuck in launching enventor due to "
+                        "this,\nTry removing a file \"%s\"\n", buf);
+        return EINA_FALSE;
+     }
+
+   //Ok, this is an unique instance!
+   FILE *fp = fopen(buf, "w");
+   if (!fp)
+     {
+        EINA_LOG_ERR("Failed to open file \"%s\"", buf);
+        return EINA_TRUE;
+     }
+   fputs("x", fp);
+   fclose(fp);
+
+   own_lock = EINA_TRUE;
+
+   return EINA_TRUE;
+}
+
+static void
+enventor_lock_remove()
+{
+   //You are not the owner of the lock.
+   if (!own_lock) return;
+
+   const char *config_home = efreet_config_home_get();
+   //Create config home directory if it doesn't exist.
+   if (!config_home || !ecore_file_exists(config_home))
+     {
+        EINA_LOG_ERR("No config home directory?! = %s", config_home);
+        return;
+     }
+
+   char buf[PATH_MAX];
+   snprintf(buf, sizeof(buf), "%s/enventor/"ENVENTOR_LOCK_FILE,
+            efreet_config_home_get());
+
+   //Just in case.
+   if (!ecore_file_exists(buf))
+     {
+        EINA_LOG_ERR("No enventor lock file?! = %s", buf);
+        return;
+     }
+
+   ecore_file_remove(buf);
+}
+
+static void
+crash_handler(int x EINA_UNUSED, siginfo_t *info EINA_UNUSED,
+              void *data EINA_UNUSED)
+{
+   EINA_LOG_ERR("Eeeek! Eventor is terminated abnormally!");
+   enventor_lock_remove();
+}
+
+static void
+sigaction_setup(void)
+{
+   //Just in case, if you are debugging using gdb,
+   //you can send signals like this. "handle SIGABRT pass"
+   //Use this for remove the enventor lock.
+
+   struct sigaction action;
+
+   memset(&action, 0x0, sizeof(action));
+   action.sa_handler = SIG_DFL;
+   action.sa_sigaction = crash_handler;
+   action.sa_flags = SA_NODEFER  | SA_RESETHAND | SA_SIGINFO;
+   sigemptyset(&action.sa_mask);
+
+   //Bus error (bad memory access)
+   sigaction(SIGBUS, &action, NULL);
+
+   //Floating pointer exception
+   sigaction(SIGFPE, &action, NULL);
+
+   //Illegal Instruction
+   sigaction(SIGILL, &action, NULL);
+
+   //Invalid memory reference
+   sigaction(SIGSEGV, &action, NULL);
+
+   //Kill
+   sigaction(SIGKILL, &action, NULL);
+
+   //Abort
+   sigaction(SIGABRT, &action, NULL);
+
+   //Stop
+   sigaction(SIGSTOP, &action, NULL);
+
+   //Interrupt from keyboard
+//   sigaction(SIGINT, &action, NULL);
+}
+
 static Eina_Bool
 init(app_data *ad, int argc, char **argv)
 {
@@ -922,9 +1068,12 @@ init(app_data *ad, int argc, char **argv)
 #endif /* set locale */
 
    elm_setup();
-
    enventor_init(argc, argv);
 
+   if (!enventor_lock_create()) return EINA_FALSE;
+   sigaction_setup();
+
+
    Eina_Bool template = EINA_FALSE;
    Eina_Bool default_edc = EINA_TRUE;
    if (!config_data_set(argc, argv, &default_edc, &template))
@@ -967,6 +1116,7 @@ term(void)
    base_gui_term();
    file_mgr_term();
    config_term();
+   enventor_lock_remove();
    enventor_shutdown();
 }
 
diff --git a/src/bin/statusbar.c b/src/bin/statusbar.c
index 9babdf6..08fb1f2 100644
--- a/src/bin/statusbar.c
+++ b/src/bin/statusbar.c
@@ -383,7 +383,7 @@ void
 stats_term(void)
 {
    stats_data *sd = g_sd;
-   EINA_SAFETY_ON_NULL_RETURN(sd);
+   if (!sd) return;
 
    eina_stringshare_del(sd->group_name);
    free(sd);
diff --git a/src/bin/tools.c b/src/bin/tools.c
index fb49677..08fcdd3 100644
--- a/src/bin/tools.c
+++ b/src/bin/tools.c
@@ -178,7 +178,7 @@ void
 tools_term(void)
 {
    tools_data *td = g_td;
-   assert(td);
+   if (!td) return;
    free(td);
 }
 
diff --git a/src/include/common.h b/src/include/common.h
index 546e308..50e16f9 100644
--- a/src/include/common.h
+++ b/src/include/common.h
@@ -99,5 +99,6 @@ EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.\n"
    #define NGETTEXT(single, plur, n) (((n)==1)? (single):(plur))
 #endif /* localization */
 
+#define ENVENTOR_LOCK_FILE ".enventor.lock"
 
 #endif