diff --git a/op/op.MoveDocument.php b/op/op.MoveDocument.php
index 87d42d120..21682eb3d 100644
--- a/op/op.MoveDocument.php
+++ b/op/op.MoveDocument.php
@@ -62,6 +62,13 @@ if($document->isLocked()) {
 	}
 }
 
+/* Check if name already exists in the folder */
+if(!$settings->_enableDuplicateDocNames) {
+	if($targetFolder->hasDocumentByName($document->getName())) {
+		UI::exitError(getMLText("folder_title", array("documentname" => htmlspecialchars($document->getName()))),getMLText("document_duplicate_name"));
+	}
+}
+
 if ($targetid != $oldFolder->getID()) {
 	if ($document->setFolder($targetFolder)) {
 		// Send notification to subscribers.
diff --git a/op/op.MoveFolder.php b/op/op.MoveFolder.php
index 09693127b..72afcf7bf 100644
--- a/op/op.MoveFolder.php
+++ b/op/op.MoveFolder.php
@@ -60,6 +60,13 @@ if ($folder->getAccessMode($user, 'moveFolder') < M_READWRITE || $targetFolder->
 	UI::exitError(getMLText("folder_title", array("foldername" => $folder->getName())),getMLText("access_denied"));
 }
 
+/* Check if name already exists in the folder */
+if(!$settings->_enableDuplicateSubFolderNames) {
+	if($targetFolder->hasSubFolderByName($folder->getName())) {
+		UI::exitError(getMLText("folder_title", array("foldername" => $folder->getName())),getMLText("subfolder_duplicate_name"));
+	}
+}
+
 $oldFolder = $folder->getParent();
 if ($folder->setParent($targetFolder)) {
 	// Send notification to subscribers.