diff --git a/controller/documentcontroller.php b/controller/documentcontroller.php
index 388b3db0..d9d4ecb3 100644
--- a/controller/documentcontroller.php
+++ b/controller/documentcontroller.php
@@ -165,7 +165,7 @@ class DocumentController extends Controller {
          ]);
          foreach ($testgroups as $testgroup) {
              $test = \OC::$server->getGroupManager()->get($testgroup);
-             if (sizeof($test->searchUsers($user)) > 0) {
+             if ($test !== null && sizeof($test->searchUsers($user)) > 0) {
                  \OC::$server->getLogger()->debug('User {user} found in {group}', [
                      'app' => $this->appName,
                      'user' => $user,
@@ -483,13 +483,14 @@ class DocumentController extends Controller {
 			$updatable = false;
 			foreach($editGroups as $editGroup) {
 				$editorGroup = \OC::$server->getGroupManager()->get($editGroup);
-				if (sizeof($editorGroup->searchUsers($editorUid)) > 0) {
+				if ($editorGroup !== null && sizeof($editorGroup->searchUsers($editorUid)) > 0) {
 					\OC::$server->getLogger()->debug("Editor {editor} is in edit group {group}", [
 						'app' => $this->appName,
 						'editor' => $editorUid,
 						'group' => $editGroup
 					]);
 					$updatable = true;
+					break;
 				}
 			}
 		}
@@ -599,8 +600,6 @@ class DocumentController extends Controller {
 
 			list($ownerid, $filename) = \OCA\Files_Versions\Storage::getUidAndFilename($res['path']);
 			$filename = '/files_versions/' . $filename . '.v' . $version;
-
-			\OC_Util::tearDownFS();
 		} else {
 			$filename = '/files' . $res['path'];
 		}