diff --git a/ajax/documentController.php b/ajax/documentController.php
index bad06d3c..4904e110 100644
--- a/ajax/documentController.php
+++ b/ajax/documentController.php
@@ -84,13 +84,8 @@ class DocumentController extends Controller{
 
 		$members = array();
 		$member = new Db_Member();
-		foreach ($sessions as $session) {
-			$sessionMembers = $member->getCollectionBy('es_id', $session['es_id']);
-			$activeMembers = array_filter($sessionMembers, function($member){
-				return $member['status']==Db_Member::MEMBER_STATUS_ACTIVE;
-			});
-
-			$members[$session['es_id']] = array_values($activeMembers);
+		foreach ($sessions as $session) {			
+			$members[$session['es_id']] = $member->getActiveCollection($session['es_id']);
 		}
 
 		\OCP\JSON::success(array('documents' => $documents,'sessions' => $sessions,'members' => $members));
diff --git a/ajax/sessionController.php b/ajax/sessionController.php
index fcb3db45..4af868d5 100644
--- a/ajax/sessionController.php
+++ b/ajax/sessionController.php
@@ -81,6 +81,23 @@ class SessionController extends Controller{
 				throw new \Exception($path . ' does not exist or is not writable for user ' . $uid);
 			}
 			
+			$member = new Db_Member();
+			$members = $member->getActiveCollection($esId);
+			$memberIds = array_map(
+				function($x){
+					return ($x['member_id']);
+				},
+				$members
+			);
+				
+			//check if member belongs to the session
+			if (!in_array($memberId, $memberIds)){
+				throw new \Exception($memberId . ' does not belong to session ' . $esId);
+			}
+			
+			// Active users except current user
+			$memberCount = count($memberIds) - 1;
+			
 			if ($view->file_exists($path)){
 				$currentHash = sha1($view->file_get_contents($path));
 				if ($currentHash !== $sessionData['genesis_hash']){
@@ -90,9 +107,15 @@ class SessionController extends Controller{
 			}
 			
 			if ($view->file_put_contents($path, $content)){
-				//Document saved successfully. Cleaning session data
-				// temporary workaround for https://github.com/owncloud/documents/issues/63
-				Db_Session::cleanUp($esId);
+				// Not a last user
+				if ($memberCount>0){
+					// Update genesis hash to prevent conflicts
+					$session->updateGenesisHash($esId, sha1($content));
+				} else {
+					// Last user. Kill session data
+					Db_Session::cleanUp($esId);
+				}
+				
 				$view->touch($path);
 			}
 			\OCP\JSON::success();
diff --git a/lib/db/member.php b/lib/db/member.php
index be270a68..c98c9680 100644
--- a/lib/db/member.php
+++ b/lib/db/member.php
@@ -39,6 +39,27 @@ class Db_Member extends Db{
 		);
 	}
 	
+	
+	public function getActiveCollection($esId){
+		$result = $this->execute('
+			SELECT `es_id`, `member_id`
+			FROM ' . self::DB_TABLE . '
+			WHERE `es_id`= ?
+				AND `status`=?
+			',
+			array(
+				$esId,
+				self::MEMBER_STATUS_ACTIVE
+			)
+		);
+		$members = $result->fetchAll();
+		if (!is_array($members)){
+			$members = array();
+		}
+		return $members;
+		
+	}
+	
 	/**
 	 * Mark members as inactive
 	 * @param string $esId - session Id
diff --git a/lib/db/session.php b/lib/db/session.php
index 2ab565a3..93fa1015 100644
--- a/lib/db/session.php
+++ b/lib/db/session.php
@@ -102,6 +102,15 @@ class Db_Session extends \OCA\Documents\Db {
 		array_unshift($this->data, $esId);
 		return parent::insert($this->data);
 	}
+	
+	public function updateGenesisHash($esId, $genesisHash){
+		return $this->execute(
+			'UPDATE `*PREFIX*documents_session` SET `genesis_hash`=? WHERE `es_id`=?',
+			array(
+				$esId, $genesisHash
+			)
+		);
+	}
 
 	public function getInfo($esId){
 		$result = $this->execute('