diff --git a/typo3/sysext/install/Classes/Controller/Action/Tool/CleanUp.php b/typo3/sysext/install/Classes/Controller/Action/Tool/CleanUp.php
index e953bc18e663ad8ae2b165e77a441c0a8f79017a..96d8abff788b37fd0622abaf4bfd6a8bc00e17fb 100644
--- a/typo3/sysext/install/Classes/Controller/Action/Tool/CleanUp.php
+++ b/typo3/sysext/install/Classes/Controller/Action/Tool/CleanUp.php
@@ -127,10 +127,12 @@ class CleanUp extends Action\AbstractAction {
 	protected function clearSelectedTables() {
 		$clearedTables = array();
 		$database = $this->getDatabaseConnection();
-		foreach ($this->postValues['values'] as $tableName => $selected) {
-			if ($selected == 1) {
-				$database->exec_TRUNCATEquery($tableName);
-				$clearedTables[] = $tableName;
+		if (isset($this->postValues['values']) && is_array($this->postValues['values'])) {
+			foreach ($this->postValues['values'] as $tableName => $selected) {
+				if ($selected == 1) {
+					$database->exec_TRUNCATEquery($tableName);
+					$clearedTables[] = $tableName;
+				}
 			}
 		}
 		if (!empty($clearedTables)) {