diff --git a/application/startup.inc.php b/application/startup.inc.php
index 3516200fa..94fca9ef9 100644
--- a/application/startup.inc.php
+++ b/application/startup.inc.php
@@ -1,49 +1,62 @@
-<?php
-// Copyright (C) 2010-2016 Combodo SARL
-//
-//   This file is part of iTop.
-//
-//   iTop is free software; you can redistribute it and/or modify	
-//   it under the terms of the GNU Affero General Public License as published by
-//   the Free Software Foundation, either version 3 of the License, or
-//   (at your option) any later version.
-//
-//   iTop is distributed in the hope that it will be useful,
-//   but WITHOUT ANY WARRANTY; without even the implied warranty of
-//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-//   GNU Affero General Public License for more details.
-//
-//   You should have received a copy of the GNU Affero General Public License
-//   along with iTop. If not, see <http://www.gnu.org/licenses/>
-
-
-/**
- * File to include to initialize the datamodel in memory
- *
- * @copyright   Copyright (C) 2010-2016 Combodo SARL
- * @license     http://opensource.org/licenses/AGPL-3.0
- */
-
-require_once(APPROOT.'/core/cmdbobject.class.inc.php');
-require_once(APPROOT.'/application/utils.inc.php');
-require_once(APPROOT.'/core/contexttag.class.inc.php');
-session_name('itop-'.md5(APPROOT));
-session_start();
-$sSwitchEnv = utils::ReadParam('switch_env', null);
-if (($sSwitchEnv != null) && (file_exists(APPCONF.$sSwitchEnv.'/'.ITOP_CONFIG_FILE)))
-{
-	$_SESSION['itop_env'] = $sSwitchEnv;
-	$sEnv = $sSwitchEnv;
-	// TODO: reset the credentials as well ??
-}
-else if (isset($_SESSION['itop_env']))
-{
-	$sEnv = $_SESSION['itop_env'];
-}
-else
-{
-	$sEnv = ITOP_DEFAULT_ENV;
-	$_SESSION['itop_env'] = ITOP_DEFAULT_ENV;
-}
-$sConfigFile = APPCONF.$sEnv.'/'.ITOP_CONFIG_FILE;
-MetaModel::Startup($sConfigFile, false /* $bModelOnly */, true /* $bAllowCache */, false /* $bTraceSourceFiles */, $sEnv);
\ No newline at end of file
+<?php
+// Copyright (C) 2010-2016 Combodo SARL
+//
+//   This file is part of iTop.
+//
+//   iTop is free software; you can redistribute it and/or modify	
+//   it under the terms of the GNU Affero General Public License as published by
+//   the Free Software Foundation, either version 3 of the License, or
+//   (at your option) any later version.
+//
+//   iTop is distributed in the hope that it will be useful,
+//   but WITHOUT ANY WARRANTY; without even the implied warranty of
+//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//   GNU Affero General Public License for more details.
+//
+//   You should have received a copy of the GNU Affero General Public License
+//   along with iTop. If not, see <http://www.gnu.org/licenses/>
+
+
+/**
+ * File to include to initialize the datamodel in memory
+ *
+ * @copyright   Copyright (C) 2010-2016 Combodo SARL
+ * @license     http://opensource.org/licenses/AGPL-3.0
+ */
+
+require_once(APPROOT.'/core/cmdbobject.class.inc.php');
+require_once(APPROOT.'/application/utils.inc.php');
+require_once(APPROOT.'/core/contexttag.class.inc.php');
+session_name('itop-'.md5(APPROOT));
+session_start();
+$sSwitchEnv = utils::ReadParam('switch_env', null);
+$bAllowCache = true;
+if (($sSwitchEnv != null) && (file_exists(APPCONF.$sSwitchEnv.'/'.ITOP_CONFIG_FILE)) && isset($_SESSION['itop_env']) && ($_SESSION['itop_env'] !== $sSwitchEnv))
+{
+	$_SESSION['itop_env'] = $sSwitchEnv;
+	$sEnv = $sSwitchEnv;
+    $bAllowCache = false;
+    // Reset the opcache since otherwise the PHP "model" files may still be cached !!
+    if (function_exists('opcache_reset'))
+    {
+        // Zend opcode cache
+        opcache_reset();
+    }
+    if (function_exists('apc_clear_cache'))
+    {
+        // APC(u) cache
+        apc_clear_cache();
+    }
+	// TODO: reset the credentials as well ??
+}
+else if (isset($_SESSION['itop_env']))
+{
+	$sEnv = $_SESSION['itop_env'];
+}
+else
+{
+	$sEnv = ITOP_DEFAULT_ENV;
+	$_SESSION['itop_env'] = ITOP_DEFAULT_ENV;
+}
+$sConfigFile = APPCONF.$sEnv.'/'.ITOP_CONFIG_FILE;
+MetaModel::Startup($sConfigFile, false /* $bModelOnly */, $bAllowCache, false /* $bTraceSourceFiles */, $sEnv);
\ No newline at end of file