diff --git a/lib/Db/AclMapper.php b/lib/Db/AclMapper.php
index c0cd89cea..d08353561 100644
--- a/lib/Db/AclMapper.php
+++ b/lib/Db/AclMapper.php
@@ -42,7 +42,7 @@ class AclMapper extends DeckMapper implements IPermissionMapper {
     }
 
     public function isOwner($userId, $aclId) {
-        $sql = 'SELECT * FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_board_acl` WHERE id = ?)';
+        $sql = 'SELECT owner FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_board_acl` WHERE id = ?)';
         $stmt = $this->execute($sql, [$aclId]);
         $row = $stmt->fetch();
         return ($row['owner'] === $userId);
diff --git a/lib/Db/BoardMapper.php b/lib/Db/BoardMapper.php
index 60f84917f..3499a1065 100644
--- a/lib/Db/BoardMapper.php
+++ b/lib/Db/BoardMapper.php
@@ -131,25 +131,6 @@ class BoardMapper extends DeckMapper implements IPermissionMapper {
         return parent::delete($entity);
     }
 
-    public function userCanView($boardId, $userInfo) {
-        $board = $this->find($boardId);
-        if($board->getOwner()===$userInfo['user']) {
-            return true;
-        }
-        try {
-            $sql = 'SELECT acl.* FROM oc_deck_boards as boards ' .
-                'JOIN oc_deck_board_acl as acl ON boards.id=acl.board_id WHERE acl.participant=? AND acl.type=\'user\' AND boards.id = ? AND boards.owner != ?';
-            $acl = $this->find($sql, [$userInfo['user'], $boardId, $userInfo['user']], $limit, $offset);
-            return true;
-        } catch (Exception $e) { }
-        try {
-            $acl = $this->find($sql, [$userInfo['user'], $boardId, $userInfo['user']], $limit, $offset);
-            return true;
-        } catch (Exception $e) {
-        }
-
-    }
-
     public function isOwner($userId, $boardId) {
         $board = $this->find($boardId);
         return ($board->getOwner() === $userId);
diff --git a/lib/Db/CardMapper.php b/lib/Db/CardMapper.php
index 3863f8c4c..b5df682f3 100644
--- a/lib/Db/CardMapper.php
+++ b/lib/Db/CardMapper.php
@@ -120,14 +120,14 @@ class CardMapper extends Mapper implements IPermissionMapper {
     }
 
     public function isOwner($userId, $cardId) {
-        $sql = 'SELECT * FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_stacks` WHERE id IN (SELECT stack_id FROM `*PREFIX*deck_cards` WHERE id = ?))';
+        $sql = 'SELECT owner FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_stacks` WHERE id IN (SELECT stack_id FROM `*PREFIX*deck_cards` WHERE id = ?))';
         $stmt = $this->execute($sql, [$cardId]);
         $row = $stmt->fetch();
         return ($row['owner'] === $userId);
     }
 
     public function findBoardId($cardId) {
-        $sql = 'SELECT * FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_stacks` WHERE id IN (SELECT stack_id FROM `*PREFIX*deck_cards` WHERE id = ?))';
+        $sql = 'SELECT id FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_stacks` WHERE id IN (SELECT stack_id FROM `*PREFIX*deck_cards` WHERE id = ?))';
         $stmt = $this->execute($sql, [$cardId]);
         $row = $stmt->fetch();
         return $row['id'];
diff --git a/lib/Db/LabelMapper.php b/lib/Db/LabelMapper.php
index 6c13b598b..34036474a 100644
--- a/lib/Db/LabelMapper.php
+++ b/lib/Db/LabelMapper.php
@@ -25,7 +25,6 @@ namespace OCA\Deck\Db;
 
 use OCP\AppFramework\Db\Entity;
 use OCP\IDb;
-use OCP\AppFramework\Db\Mapper;
 
 
 class LabelMapper extends DeckMapper implements IPermissionMapper {
@@ -84,7 +83,7 @@ class LabelMapper extends DeckMapper implements IPermissionMapper {
 	}
 
     public function isOwner($userId, $labelId) {
-        $sql = 'SELECT * FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_labels` WHERE id = ?)';
+        $sql = 'SELECT owner FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_labels` WHERE id = ?)';
         $stmt = $this->execute($sql, [$labelId]);
         $row = $stmt->fetch();
         return ($row['owner'] === $userId);
diff --git a/lib/Db/StackMapper.php b/lib/Db/StackMapper.php
index a07b9e4c8..e8ba0e86e 100644
--- a/lib/Db/StackMapper.php
+++ b/lib/Db/StackMapper.php
@@ -62,7 +62,7 @@ class StackMapper extends Mapper implements IPermissionMapper {
     }
 
     public function isOwner($userId, $stackId) {
-        $sql = 'SELECT * FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_stacks` WHERE id = ?)';
+        $sql = 'SELECT owner FROM `*PREFIX*deck_boards` WHERE `id` IN (SELECT board_id FROM `*PREFIX*deck_stacks` WHERE id = ?)';
         $stmt = $this->execute($sql, [$stackId]);
         $row = $stmt->fetch();
         return ($row['owner'] === $userId);
diff --git a/lib/Middleware/SharingMiddleware.php b/lib/Middleware/SharingMiddleware.php
index 3a5cc3141..5d057b8c1 100644
--- a/lib/Middleware/SharingMiddleware.php
+++ b/lib/Middleware/SharingMiddleware.php
@@ -29,6 +29,7 @@ use OCA\Deck\Controller\LabelController;
 use OCA\Deck\Controller\PageController;
 use OCA\Deck\Controller\ShareController;
 use OCA\Deck\NoPermissionException;
+use OCA\Deck\NotFoundException;
 use \OCP\AppFramework\Middleware;
 use OCP\IContainer;
 use OCP\IRequest;
@@ -192,15 +193,18 @@ class SharingMiddleware extends Middleware {
 	 * @return bool
 	 */
 	public function checkMapperPermission($permission, $userId, $mapper, $id) {
-		// FIXME: This fails with no permission if $id doesn't exist
-		// We need some fallback to doesn't exist here
-
-		// is owner
+		// check if current user is owner
 		if ($mapper->isOwner($userId, $id)) {
 			return true;
 		}
-		// check if is in acl
+		
+		// find related board
 		$boardId = $mapper->findBoardId($id);
+		if(!$boardId) {
+			throw new NotFoundException("Entity not found");
+		}
+		// check if is in acl
+
 		$acls = $this->aclMapper->findAll($boardId);
 		// check for users
 		foreach ($acls as $acl) {
@@ -234,6 +238,12 @@ class SharingMiddleware extends Middleware {
 				"message" => $exception->getMessage()
 			], 401);
 		}
+		if (is_a($exception, '\OCA\Deck\NotFoundException')) {
+			return new JSONResponse([
+				"status" => 404,
+				"message" => $exception->getMessage()
+			], 404);
+		}
 		throw $exception;
 	}
 
diff --git a/lib/NotFoundException.php b/lib/NotFoundException.php
index f48e979fd..90f2d9558 100644
--- a/lib/NotFoundException.php
+++ b/lib/NotFoundException.php
@@ -24,12 +24,9 @@
 namespace OCA\Deck;
 
 
-class NoPermissionException extends \Exception {
+class NotFoundException extends \Exception {
 
-	public function __construct($message, $controller=null, $method=null) {
+	public function __construct($message) {
 		parent::__construct($message);
-		if($controller && $method) {
-			$this->message = get_class($controller) . "#" . $method . ": " . $message;
-		}
 	}
 }
\ No newline at end of file