diff --git a/js/controller/BoardController.js b/js/controller/BoardController.js
index e6599f2f8..41729c8aa 100644
--- a/js/controller/BoardController.js
+++ b/js/controller/BoardController.js
@@ -323,7 +323,7 @@ app.controller('BoardController', function ($rootScope, $scope, $stateParams, St
 		// remove from board data
 		var i = BoardService.getCurrent().labels.indexOf(label);
 		BoardService.getCurrent().labels.splice(i, 1);
-		
+
 		// remove from cards
 		var cards = CardService.data;
 		for (var card in cards) {
@@ -346,11 +346,21 @@ app.controller('BoardController', function ($rootScope, $scope, $stateParams, St
 			BoardService.getCurrent().labels.push(data);
 			$scope.status.createLabel = false;
 			$scope.newLabel = {};
+		}).catch((err) => {
+			OC.Notification.showTemporary(err);
 		});
 	};
+
+	$scope.labelUpdateBefore = function (label) {
+		label.renameTitle = label.title;
+	};
+
 	$scope.labelUpdate = function (label) {
 		label.edit = false;
-		LabelService.update(label);
+		LabelService.update(label).catch((err) => {
+			label.title = label.renameTitle;
+			OC.Notification.showTemporary(err);
+		});
 
 		// update labels in UI
 		var cards = CardService.data;
diff --git a/js/service/ApiService.js b/js/service/ApiService.js
index 077ed4dd7..d5599e69a 100644
--- a/js/service/ApiService.js
+++ b/js/service/ApiService.js
@@ -119,7 +119,7 @@ app.factory('ApiService', function ($http, $q) {
 			self.add(response.data);
 			deferred.resolve(response.data);
 		}, function (error) {
-			deferred.reject('Fetching' + self.endpoint + ' failed');
+			deferred.reject(error.data.message);
 		});
 		return deferred.promise;
 	};
@@ -131,7 +131,7 @@ app.factory('ApiService', function ($http, $q) {
 			self.add(response.data);
 			deferred.resolve(response.data);
 		}, function (error) {
-			deferred.reject('Updating ' + self.endpoint + ' failed');
+			deferred.reject(error.data.message);
 		});
 		return deferred.promise;
 
diff --git a/lib/Service/LabelService.php b/lib/Service/LabelService.php
index e46ee39ab..f596b19a2 100644
--- a/lib/Service/LabelService.php
+++ b/lib/Service/LabelService.php
@@ -91,6 +91,17 @@ class LabelService {
 		}
 
 		$this->permissionService->checkPermission(null, $boardId, Acl::PERMISSION_MANAGE);
+
+		$boardLabels = $this->labelMapper->findAll($boardId);
+		if (\is_array($boardLabels)) {
+			foreach($boardLabels as $boardLabel) {
+				if ($boardLabel->getTitle() === $title) {
+					throw new BadRequestException('title must be unique');
+					break;
+				}
+			}
+		}
+
 		if ($this->boardService->isArchived(null, $boardId)) {
 			throw new StatusException('Operation not allowed. This board is archived.');
 		}
@@ -143,7 +154,7 @@ class LabelService {
 			throw new BadRequestException('label id must be a number');
 		}
 
-		if ($title === false || $title === null) {
+		if ($title === false || $title === null || $title === "") {
 			throw new BadRequestException('title must be provided');
 		}
 
@@ -152,10 +163,26 @@ class LabelService {
 		}
 
 		$this->permissionService->checkPermission($this->labelMapper, $id, Acl::PERMISSION_MANAGE);
+
+		$label = $this->find($id);
+
+		$boardLabels = $this->labelMapper->findAll($label->getBoardId());
+		if (\is_array($boardLabels)) {
+			foreach($boardLabels as $boardLabel) {
+				if ($boardLabel->getId() === $label->getId()) {
+					continue;
+				}
+				if ($boardLabel->getTitle() === $title) {
+					throw new BadRequestException('title must be unique');
+					break;
+				}
+			}
+		}
+
 		if ($this->boardService->isArchived($this->labelMapper, $id)) {
 			throw new StatusException('Operation not allowed. This board is archived.');
 		}
-		$label = $this->find($id);
+
 		$label->setTitle($title);
 		$label->setColor($color);
 		$this->changeHelper->boardChanged($label->getBoardId());
diff --git a/templates/part.board.sidebarView.php b/templates/part.board.sidebarView.php
index db35568be..928510b01 100644
--- a/templates/part.board.sidebarView.php
+++ b/templates/part.board.sidebarView.php
@@ -105,7 +105,7 @@
                         </div>
                     </div>
                     <a ng-if="boardservice.canManage() && label.edit" ng-click="labelUpdate(label)" class="icon" title="<?php p($l->t('Update tag')); ?>"><i class="icon icon-checkmark" ></i><span class="hidden-visually"><?php p($l->t('Update tag')); ?></span></a>
-                    <a ng-if="boardservice.canManage() && !label.edit" ng-click="label.edit=true" class="icon" title="<?php p($l->t('Edit tag')); ?>"><i class="icon icon-rename"></i><span class="hidden-visually"><?php p($l->t('Edit tag')); ?></span></a>
+                    <a ng-if="boardservice.canManage() && !label.edit" ng-click="labelUpdateBefore(label); label.edit=true" class="icon" title="<?php p($l->t('Edit tag')); ?>"><i class="icon icon-rename"></i><span class="hidden-visually"><?php p($l->t('Edit tag')); ?></span></a>
                     <a ng-if="boardservice.canManage()" ng-click="labelDelete(label)" class="icon" title="<?php p($l->t('Delete tag')); ?>"><i class="icon icon-delete" ></i><span class="hidden-visually"><?php p($l->t('Delete tag')); ?></span></a>
                 </li>
                 <li ng-if="status.createLabel">