diff --git a/SoObjects/Appointments/SOGoComponentOccurence.m b/SoObjects/Appointments/SOGoComponentOccurence.m
index f81a73f5a..c8a16030c 100644
--- a/SoObjects/Appointments/SOGoComponentOccurence.m
+++ b/SoObjects/Appointments/SOGoComponentOccurence.m
@@ -1,6 +1,6 @@
 /* SOGoComponentOccurence.m - this file is part of SOGo
  * 
- * Copyright (C) 2008-2014 Inverse inc.
+ * Copyright (C) 2008-2016 Inverse inc.
  *
  * This file is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -211,6 +211,13 @@
   return [container saveComponent: newObject];
 }
 
+- (NSException *) saveComponent: (iCalRepeatableEntityObject *) newObject
+                          force: (BOOL) forceSave
+{
+  return [container saveComponent: newObject
+                            force: forceSave];
+}
+
 #warning most of SOGoCalendarComponent and SOGoComponentOccurence share the same external interface... \
   they should be siblings or SOGoComponentOccurence the parent class of SOGoCalendarComponent...
 - (NSException *) changeParticipationStatus: (NSString *) newStatus
diff --git a/UI/Scheduler/UIxAppointmentActions.m b/UI/Scheduler/UIxAppointmentActions.m
index 7568dde44..a96129b52 100644
--- a/UI/Scheduler/UIxAppointmentActions.m
+++ b/UI/Scheduler/UIxAppointmentActions.m
@@ -22,6 +22,7 @@
 #import <Foundation/NSDictionary.h>
 #import <Foundation/NSString.h>
 #import <Foundation/NSArray.h>
+#import <Foundation/NSValue.h>
 
 #import <NGExtensions/NSObject+Values.h>
 
@@ -68,6 +69,7 @@
   SOGoAppointmentFolder *targetCalendar, *sourceCalendar;
   SOGoAppointmentFolders *folders;
   BOOL forceSave;
+  id error;
 
   rq = [context request];
   params = [[rq contentAsString] objectFromJSONString];
@@ -76,7 +78,7 @@
   startDelta = [params objectForKey: @"start"];
   durationDelta = [params objectForKey: @"duration"];
   destionationCalendar = [params objectForKey: @"destination"];
-  forceSave = NO;
+  forceSave = [[params objectForKey: @"ignoreConflicts"] boolValue];
 
   if (daysDelta || startDelta || durationDelta)
     {
@@ -150,8 +152,11 @@
           if ([ex respondsToSelector: @selector(httpStatus)])
             httpStatus = [ex httpStatus];
 
+          error = [[ex reason] objectFromJSONString];
+          if (error == nil)
+            error = [ex reason];
           jsonResponse = [NSDictionary dictionaryWithObjectsAndKeys:
-                                         [ex reason], @"message",
+                                         error, @"message",
                                        nil];
 
           response = [self responseWithStatus: httpStatus
diff --git a/UI/Scheduler/UIxAppointmentEditor.m b/UI/Scheduler/UIxAppointmentEditor.m
index 8cc46110c..507f71890 100644
--- a/UI/Scheduler/UIxAppointmentEditor.m
+++ b/UI/Scheduler/UIxAppointmentEditor.m
@@ -467,6 +467,7 @@
   SOGoAppointmentObject *co;
   SoSecurityManager *sm;
   WORequest *request;
+  id error;
 
   unsigned int httpStatus;
   BOOL forceSave;
@@ -490,7 +491,7 @@
   else
     {
       [self setAttributes: params];
-      forceSave = NO;
+      forceSave = [[params objectForKey: @"ignoreConflicts"] boolValue];
 
       if ([event hasRecurrenceRules])
         [self _adjustRecurrentRules];
@@ -546,9 +547,11 @@
       if ([ex respondsToSelector: @selector(httpStatus)])
         httpStatus = [ex httpStatus];
 
+      error = [[ex reason] objectFromJSONString];
+      if (error == nil)
+        error = [ex reason];
       jsonResponse = [NSDictionary dictionaryWithObjectsAndKeys:
-                                     [ex reason], @"message",
-                                   nil];
+                                     error, @"message", nil];
     }
   else
     {
diff --git a/UI/Templates/SchedulerUI/UIxAppointmentEditorTemplate.wox b/UI/Templates/SchedulerUI/UIxAppointmentEditorTemplate.wox
index 134b25b54..79666f52a 100644
--- a/UI/Templates/SchedulerUI/UIxAppointmentEditorTemplate.wox
+++ b/UI/Templates/SchedulerUI/UIxAppointmentEditorTemplate.wox
@@ -275,7 +275,7 @@
         </div>
       </md-dialog-content>
       <!-- cancel/reset/save -->
-      <md-dialog-actions>
+      <md-dialog-actions ng-hide="editor.attendeeConflictError">
         <md-button type="button" ng-click="editor.cancel()">
           <var:string label:value="Cancel"/>
         </md-button>
@@ -287,6 +287,48 @@
           <var:string label:value="Save"/>
         </md-button>
       </md-dialog-actions>
+
+      <!-- attendee availability conflict -->
+      <md-dialog-actions class="md-default-theme md-bg md-warn"
+                         ng-show="editor.attendeeConflictError">
+        <div class="md-flex"><var:string label:value="A time conflict exists with one or more attendees.\nWould you like to keep the current settings anyway?"/></div>
+        <md-button class="md-icon-button" ng-click="editor.attendeeConflictError = false">
+          <md-icon label:aria-label="Close">close</md-icon>
+        </md-button>
+      </md-dialog-actions>
+      <md-dialog-actions class="md-default-theme md-bg md-warn"
+                         ng-show="editor.attendeeConflictError">
+          <div class="md-flex">
+            <md-icon>person</md-icon> {{editor.attendeeConflictError.attendee_name}} ({{editor.attendeeConflictError.attendee_email}})
+          </div>
+      </md-dialog-actions>
+      <md-dialog-actions class="md-default-theme md-bg md-warn"
+                         ng-show="editor.attendeeConflictError"
+                         ng-repeat="conflict in editor.attendeeConflictError.conflicts">
+        <md-icon>schedule</md-icon>
+        <div class="pseudo-input-container">
+          <label class="pseudo-input-label"><var:string label:value="From"/></label>
+          <div>{{conflict.startDate}} <md-icon>trending_flat</md-icon></div>
+        </div>
+        <div class="pseudo-input-container md-flex">
+          <label class="pseudo-input-label"><var:string label:value="To"/></label>
+          <div>{{conflict.endDate}}</div>
+        </div>
+      </md-dialog-actions>
+      <md-dialog-actions ng-show="editor.attendeeConflictError">
+        <md-button type="button" ng-click="editor.cancel()">
+          <var:string label:value="Cancel"/>
+        </md-button>
+        <md-button type="button"
+                   ng-click="editor.attendeeConflictError = false">
+          <var:string label:value="Edit"/>
+        </md-button>
+        <md-button class="md-warn" type="button"
+                   ng-click="editor.save(eventForm, { ignoreConflicts: true })"
+                   ng-disabled="editor.eventForm.$invalid">
+          <var:string label:value="Save"/>
+        </md-button>
+      </md-dialog-actions>
     </form>
   </md-dialog>
 </container>
diff --git a/UI/Templates/SchedulerUI/UIxCalMainView.wox b/UI/Templates/SchedulerUI/UIxCalMainView.wox
index d448c3d4e..d248c9486 100644
--- a/UI/Templates/SchedulerUI/UIxCalMainView.wox
+++ b/UI/Templates/SchedulerUI/UIxCalMainView.wox
@@ -737,4 +737,39 @@
     </md-dialog>
   </script>
 
+  <!-- modal for attendee availability conflict -->
+  <script type="text/ng-template" id="UIxAttendeeConflictDialog">
+    <md-dialog flex="60" flex-xs="100">
+      <md-dialog-content class="md-dialog-content">
+        <h2 class="md-title">Warning</h2>
+        <p><var:string label:value="A time conflict exists with one or more attendees.\nWould you like to keep the current settings anyway?"/></p>
+        <md-list>
+          <md-list-item>
+            <md-icon>person</md-icon> {{$AttendeeConflictDialogController.conflictError.attendee_name}} ({{$AttendeeConflictDialogController.conflictError.attendee_email}})
+          </md-list-item>
+          <md-list-item ng-repeat="conflict in $AttendeeConflictDialogController.conflictError.conflicts">
+            <md-icon>schedule</md-icon>
+            <div class="pseudo-input-container">
+              <label class="pseudo-input-label"><var:string label:value="From"/></label>
+              <div>{{conflict.startDate}}</div>
+            </div>
+            <div class="pseudo-input-container md-flex">
+              <label class="pseudo-input-label"><var:string label:value="To"/></label>
+              <div>{{conflict.endDate}}</div>
+            </div>
+          </md-list-item>
+        </md-list>
+      </md-dialog-content>
+      <md-dialog-actions>
+        <md-button type="button" ng-click="$AttendeeConflictDialogController.cancel()">
+          <var:string label:value="Cancel"/>
+        </md-button>
+        <md-button class="md-warn" type="button"
+                   ng-click="$AttendeeConflictDialogController.save()">
+          <var:string label:value="Save"/>
+        </md-button>
+      </md-dialog-actions>
+    </md-dialog>
+  </script>
+
 </var:component>
diff --git a/UI/WebServerResources/js/Common/navController.js b/UI/WebServerResources/js/Common/navController.js
index a6f78b5d8..934de0961 100644
--- a/UI/WebServerResources/js/Common/navController.js
+++ b/UI/WebServerResources/js/Common/navController.js
@@ -66,7 +66,7 @@
 
     function onHttpError(event, response) {
       var message;
-      if (response.data && response.data.message)
+      if (response.data && response.data.message && angular.isString(response.data.message))
         message = response.data.message;
       else if (response.status)
         message = response.statusText;
@@ -85,7 +85,7 @@
           position: 'top right'
         });
       else
-        console.debug('untrap error');
+        $log.debug('untrap error');
     }
 
     // Listen to HTTP errors broadcasted from HTTP interceptor
diff --git a/UI/WebServerResources/js/Scheduler/CalendarListController.js b/UI/WebServerResources/js/Scheduler/CalendarListController.js
index 93793a05c..644371def 100644
--- a/UI/WebServerResources/js/Scheduler/CalendarListController.js
+++ b/UI/WebServerResources/js/Scheduler/CalendarListController.js
@@ -162,8 +162,7 @@
         component.setDelta(coordinates.duration * 15);
         newComponent(null, component).finally(function() {
           $timeout(function() {
-            Component.$ghost.pointerHandler = null;
-            Component.$ghost.component = null;
+            Component.$resetGhost();
           });
         });
       }
@@ -186,8 +185,11 @@
           // Immediately perform the adjustments
           component.$adjust(params).then(function() {
             $rootScope.$emit('calendars:list');
+          }, function(response) {
+            onComponentAdjustError(response, component, params);
+          }).finally(function() {
             $timeout(function() {
-              Component.$ghost = {};
+              Component.$resetGhost();
             });
           });
         else if (component.occurrenceId) {
@@ -199,7 +201,7 @@
               params: params
             },
             template: [
-              '<md-dialog flex="50" md-flex="80" sm-flex="90">',
+              '<md-dialog flex="50" sm-flex="80" xs-flex="90">',
               '  <md-dialog-content class="md-dialog-content">',
               '    <p>' + l('editRepeatingItem') + '</p>',
               '  </md-dialog-content>',
@@ -214,7 +216,7 @@
             $rootScope.$emit('calendars:list');
           }).finally(function() {
             $timeout(function() {
-              Component.$ghost = {};
+              Component.$resetGhost();
             });
           });
         }
@@ -226,13 +228,58 @@
       RecurrentComponentDialogController.$inject = ['$scope', '$mdDialog', 'component', 'params'];
       function RecurrentComponentDialogController($scope, $mdDialog, component, params) {
         $scope.updateThisOccurrence = function() {
-          component.$adjust(params).then($mdDialog.hide, $mdDialog.cancel);
+          component.$adjust(params).then($mdDialog.hide, function(response) {
+            $mdDialog.cancel().then(function() {
+              onComponentAdjustError(response, component, params);
+            });
+          });
         };
         $scope.updateAllOccurrences = function() {
           delete component.occurrenceId;
-          component.$adjust(params).then($mdDialog.hide, $mdDialog.cancel);
+          component.$adjust(params).then($mdDialog.hide, function(response) {
+            $mdDialog.cancel().then(function() {
+              onComponentAdjustError(response, component, params);
+            });
+          });
         };
       }
+
+      function onComponentAdjustError(response, component, params) {
+        if (response.status == 403 &&
+            response.data && response.data.message && angular.isObject(response.data.message)) {
+          $mdDialog.show({
+            parent: angular.element(document.body),
+            clickOutsideToClose: false,
+            escapeToClose: false,
+            templateUrl: 'UIxAttendeeConflictDialog',
+            controller: AttendeeConflictDialogController,
+            controllerAs: '$AttendeeConflictDialogController',
+            locals: {
+              component: component,
+              params: params,
+              conflictError: response.data.message
+            }
+          }).then(function() {
+            $rootScope.$emit('calendars:list');
+          });
+        }
+      }
+
+      /**
+       * @ngInject
+       */
+      AttendeeConflictDialogController.$inject = ['$scope', '$mdDialog', 'component', 'params', 'conflictError'];
+      function AttendeeConflictDialogController($scope, $mdDialog, component, params, conflictError) {
+        var vm = this;
+
+        vm.conflictError = conflictError;
+        vm.cancel = $mdDialog.cancel;
+        vm.save = save;
+
+        function save() {
+          component.$adjust(angular.extend({ ignoreConflicts: true }, params)).then($mdDialog.hide);
+        }
+      }
     }
 
     function filter(filterpopup) {
diff --git a/UI/WebServerResources/js/Scheduler/Component.service.js b/UI/WebServerResources/js/Scheduler/Component.service.js
index 7390fbe84..a6ab49487 100644
--- a/UI/WebServerResources/js/Scheduler/Component.service.js
+++ b/UI/WebServerResources/js/Scheduler/Component.service.js
@@ -414,6 +414,15 @@
     });
   };
 
+  /**
+   * @function $resetGhost
+   * @desc Prepare the ghost object for the next drag by resetting appropriate attributes
+   */
+  Component.$resetGhost = function() {
+    this.$ghost.pointerHandler = null;
+    this.$ghost.component = null;
+  };
+
   /**
    * @function $parseDate
    * @desc Parse a date string with format YYYY-MM-DDTHH:MM
@@ -1035,8 +1044,9 @@
    * @function $save
    * @memberof Component.prototype
    * @desc Save the component to the server.
+   * @param {object} extraAttributes - additional attributes to send to the server
    */
-  Component.prototype.$save = function() {
+  Component.prototype.$save = function(extraAttributes) {
     var _this = this, options, path, component, date, dlp;
 
     component = this.$omit();
@@ -1106,6 +1116,8 @@
     if (this.occurrenceId)
       path.push(this.occurrenceId);
 
+    angular.extend(component, extraAttributes);
+
     return Component.$$resource.save(path.join('/'), component, options)
       .then(function(data) {
         // Make a copy of the data for an eventual reset
diff --git a/UI/WebServerResources/js/Scheduler/ComponentController.js b/UI/WebServerResources/js/Scheduler/ComponentController.js
index 3bc62fdfd..fc5f3df36 100644
--- a/UI/WebServerResources/js/Scheduler/ComponentController.js
+++ b/UI/WebServerResources/js/Scheduler/ComponentController.js
@@ -162,6 +162,7 @@
     vm.addAttachUrl = addAttachUrl;
     vm.cancel = cancel;
     vm.save = save;
+    vm.attendeeConflictError = false;
     vm.attendeesEditor = {
       days: getDays(),
       hours: getHours()
@@ -217,15 +218,18 @@
       }
     }
 
-    function save(form) {
+    function save(form, options) {
       if (form.$valid) {
-        vm.component.$save()
+        vm.component.$save(options)
           .then(function(data) {
             $rootScope.$emit('calendars:list');
             $mdDialog.hide();
             Alarm.getAlarms();
-          }, function(data, status) {
-            $log.debug('failed');
+          }, function(response) {
+            if (response.status == 403 &&
+                response.data && response.data.message && angular.isObject(response.data.message)) {
+              vm.attendeeConflictError = response.data.message;
+            }
           });
       }
     }