diff --git a/setup/feature_removal/ModelReflectionSerializer.php b/setup/feature_removal/ModelReflectionSerializer.php
index 8b04427b7..53ed1d5df 100644
--- a/setup/feature_removal/ModelReflectionSerializer.php
+++ b/setup/feature_removal/ModelReflectionSerializer.php
@@ -36,19 +36,6 @@ class ModelReflectionSerializer
 	{
 		IssueLog::Info(__METHOD__, null, ['env' => $sEnv]);
 
-		$sCurrentEnvt = MetaModel::GetEnvironment();
-		if ($sCurrentEnvt === $sEnv) {
-			$aClasses = MetaModel::GetClasses();
-			if (count($aClasses) === 0) {
-				//MetaModel not started yet
-				$sConfFile = utils::GetConfigFilePath($sEnv);
-
-				MetaModel::Startup($sConfFile, false /* $bModelOnly */, false /* $bAllowCache */, false /* $bTraceSourceFiles */, $sEnv);
-				$aClasses = MetaModel::GetClasses();
-			}
-			return $aClasses;
-		}
-
 		$sPHPExec = trim(utils::GetConfig()->Get('php_path'));
 		$sOutput = "";
 		$iRes = 0;
diff --git a/setup/modulediscovery/ModuleFileReader.php b/setup/modulediscovery/ModuleFileReader.php
index 9fbcd634c..b87df8895 100644
--- a/setup/modulediscovery/ModuleFileReader.php
+++ b/setup/modulediscovery/ModuleFileReader.php
@@ -16,6 +16,7 @@ use PhpParser\Node\Stmt\ElseIf_;
 use PhpParser\Node\Stmt\Expression;
 use PhpParser\Node\Stmt\If_;
 use PhpParser\ParserFactory;
+use SetupLog;
 
 require_once __DIR__.'/ModuleFileReaderException.php';
 require_once APPROOT.'sources/PhpParser/Evaluation/PhpExpressionEvaluator.php';
@@ -143,6 +144,7 @@ class ModuleFileReader
 			}
 			// Replace the main function call by an assignment to a variable, as an array...
 			$sModuleFileContents = str_replace(['SetupWebPage::AddModule', 'ModuleDiscovery::AddModule'], '$aModuleInfo = array', $sModuleFileContents);
+			SetupLog::Debug(__METHOD__, null, ['module_file' => $sModuleFilePath]);
 			eval($sModuleFileContents); // Assigns $aModuleInfo
 
 			if (count($aModuleInfo) === 0) {
diff --git a/setup/runtimeenv.class.inc.php b/setup/runtimeenv.class.inc.php
index 74d9667d9..8d0ace623 100644
--- a/setup/runtimeenv.class.inc.php
+++ b/setup/runtimeenv.class.inc.php
@@ -1126,7 +1126,9 @@ class RunTimeEnvironment
 			}
 
 			if (is_null($aSelectedModules) || in_array($sModuleId, $aSelectedModules)) {
-				$aArgs = [MetaModel::GetConfig(), $aModule['installed_version'], $aModule['available_version']];
+				$oConfig = MetaModel::GetConfig();
+				$oConfig->Set('access_mode', ACCESS_FULL);
+				$aArgs = [$oConfig, $aModule['installed_version'], $aModule['available_version']];
 				RunTimeEnvironment::CallInstallerHandler($aModule, $sHandlerName, $aArgs);
 			}
 		}
@@ -1193,6 +1195,9 @@ class RunTimeEnvironment
 	 */
 	public function LoadData($aAvailableModules, $bSampleData, $aSelectedModules = null)
 	{
+		$oConfig = MetaModel::GetConfig();
+		$oConfig->Set('access_mode', ACCESS_FULL);
+
 		$oDataLoader = new XMLDataLoader();
 
 		CMDBObject::SetCurrentChangeFromParams("Initialization from XML files for the selected modules ");
@@ -1326,9 +1331,6 @@ class RunTimeEnvironment
 	{
 		$oSetupAudit = new SetupAudit(ITOP_DEFAULT_ENV, $this->sBuildEnv);
 
-		//Make sure the MetaModel is started before analysing for issues
-		$sConfFile = utils::GetConfigFilePath(ITOP_DEFAULT_ENV);
-		MetaModel::Startup($sConfFile, false, false); // Start on production environment
 		$oSetupAudit->RunDataAudit(true);
 		$iCount = $oSetupAudit->GetDataToCleanupCount();
 
@@ -1537,6 +1539,15 @@ class RunTimeEnvironment
 		$oBackup->CreateCompressedBackup($sTargetFile, $sSourceConfigFile);
 	}
 
+	/**
+		* @param \Config $oConfig
+		* @return void
+	 */
+	public function EnterMaintenanceMode(Config $oConfig)
+	{
+		SetupUtils::EnterMaintenanceMode($oConfig);
+	}
+
 	public function EnterReadOnlyMode(Config $oConfig)
 	{
 		if ($this->GetFinalEnv() != 'production') {
@@ -1550,6 +1561,11 @@ class RunTimeEnvironment
 		SetupUtils::EnterReadOnlyMode($oConfig);
 	}
 
+	public function ExitMaintenanceMode(): void
+	{
+		SetupUtils::ExitMaintenanceMode();
+	}
+
 	public function ExitReadOnlyMode()
 	{
 		if ($this->GetFinalEnv() != 'production') {
diff --git a/setup/sequencers/ApplicationInstallSequencer.php b/setup/sequencers/ApplicationInstallSequencer.php
index fe68981fe..bfa612d68 100644
--- a/setup/sequencers/ApplicationInstallSequencer.php
+++ b/setup/sequencers/ApplicationInstallSequencer.php
@@ -89,6 +89,7 @@ class ApplicationInstallSequencer extends StepSequencer
 					return $this->ComputeNextStep($sStep);
 
 				case 'migrate-before':
+					$this->oRunTimeEnvironment->EnterMaintenanceMode($this->GetConfig());
 					if (array_key_exists($sStep, $this->oParams->Get('optional_steps', []))) {
 						$this->oRunTimeEnvironment->MigrateDataBeforeUpdateStructure($this->oParams->Get('mode'), $this->GetConfig());
 					}
@@ -139,6 +140,7 @@ class ApplicationInstallSequencer extends StepSequencer
 				case 'commit':
 					$this->oRunTimeEnvironment->Commit();
 					$this->oRunTimeEnvironment->ExitReadOnlyMode();
+					$this->oRunTimeEnvironment->ExitMaintenanceMode();
 					return $this->GetNextStep('', 'Completed', 100);
 
 				default:
diff --git a/setup/sequencers/StepSequencer.php b/setup/sequencers/StepSequencer.php
index e80d986f1..bb7515299 100644
--- a/setup/sequencers/StepSequencer.php
+++ b/setup/sequencers/StepSequencer.php
@@ -159,6 +159,11 @@ abstract class StepSequencer
 		file_put_contents(APPROOT.'log/'.$sFileName.'.xml', $sSafeXml);
 	}
 
+	/**
+	* @return \Config
+	* @throws \ConfigException
+	* @throws \CoreException
+	 */
 	protected function GetConfig()
 	{
 		if (! is_null($this->oTestConfig)) {