diff --git a/setup/setuputils.class.inc.php b/setup/setuputils.class.inc.php
index 0770b183a..4a7bb5fc3 100644
--- a/setup/setuputils.class.inc.php
+++ b/setup/setuputils.class.inc.php
@@ -1602,7 +1602,7 @@ JS
 			$aDirsToScan[] = $sExtraDir;
 		}
 		$oProductionEnv = new RunTimeEnvironment();
-		$aRemovedExtensionCodes = $oWizard->GetParameter('removed_extensions', []);
+		$aRemovedExtensionCodes = json_decode($oWizard->GetParameter('removed_extensions'), true) ?? [];
 		$oExtensionsMap = new iTopExtensionsMap('production', $aDirsToScan);
 		$oExtensionsMap->DeclareExtensionAsRemoved($aRemovedExtensionCodes);
 
diff --git a/setup/wizardsteps.class.inc.php b/setup/wizardsteps.class.inc.php
index 680e3a747..12db0dadd 100644
--- a/setup/wizardsteps.class.inc.php
+++ b/setup/wizardsteps.class.inc.php
@@ -2272,7 +2272,7 @@ class WizStepSummary extends WizardStep
 		$oPage->add('</div>');
 		$oPage->add('<div class="closed"><span class="title ibo-setup-summary-title">Extensions to be uninstalled</span>');
 
-		$aExtensionsRemoved = json_decode($this->oWizard->GetParameter('removed_extensions'), true);
+		$aExtensionsRemoved = json_decode($this->oWizard->GetParameter('removed_extensions'), true) ?? [];
 		$aExtensionsNotUninstallable = json_decode($this->oWizard->GetParameter('extensions_not_uninstallable'));
 		$sExtensionsRemoved = '';
 		if (count($aExtensionsRemoved) > 0) {