diff --git a/calendar/inc/class.calendar_boupdate.inc.php b/calendar/inc/class.calendar_boupdate.inc.php
index c43ad0bf38..193ad458ec 100644
--- a/calendar/inc/class.calendar_boupdate.inc.php
+++ b/calendar/inc/class.calendar_boupdate.inc.php
@@ -1812,6 +1812,40 @@ class calendar_boupdate extends calendar_bo
 		return true;
 	}
 
+	/**
+	 * Check alarms and move them if needed
+	 *
+	 * Used when the start time has changed, and alarms need to be updated
+	 *
+	 * @param array $event
+	 * @param array $old_event
+	 * @param egw_time $instance_date For recurring events, this is the date we
+	 *	are dealing with
+	 */
+	function check_move_alarms(Array &$event, Array $old_event = null, egw_time $instance_date = null)
+	{
+		if ($old_event !== null && $event['start'] == $old_event['start']) return;
+
+		$time = new egw_time($event['start']);
+		if(!is_array($event['alarm']))
+		{
+			$event['alarm'] = $this->so->read_alarms($event['id']);
+		}
+
+		foreach($event['alarm'] as $id => &$alarm)
+		{
+			if($event['recur_type'] != MCAL_RECUR_NONE)
+			{
+				calendar_so::shift_alarm($event, $alarm, $instance_date->format('ts'));
+			}
+			else if ($alarm['time'] !== $time->format('ts') - $alarm['offset'])
+			{
+				$alarm['time'] = $time->format('ts') - $alarm['offset'];
+				$this->save_alarm($event['id'], $alarm);
+			}
+		}
+	}
+
 	/**
 	 * saves a new or updated alarm
 	 *
diff --git a/calendar/inc/class.calendar_so.inc.php b/calendar/inc/class.calendar_so.inc.php
index 27fc3f10e0..e6d37ba01f 100644
--- a/calendar/inc/class.calendar_so.inc.php
+++ b/calendar/inc/class.calendar_so.inc.php
@@ -1688,15 +1688,17 @@ ORDER BY cal_user_type, cal_usre_id
 	 *
 	 * @param array $_event event with optional 'cal_' prefix in keys
 	 * @param array &$alarm
+	 * @param int $timestamp For recurring events, this is the date we
+	 *	are dealing with, default is now.
 	 * @return boolean true if alarm could be shifted, false if not
 	 */
-	public static function shift_alarm(array $_event, array &$alarm)
+	public static function shift_alarm(array $_event, array &$alarm, $timestamp)
 	{
 		if ($_event['recur_type'] == MCAL_RECUR_NONE)
 		{
 			return false;
 		}
-		$start = (int)time() + $alarm['offset'];
+		$start = $timestamp ? $timestamp : (int)time() + $alarm['offset'];
 		$event = egw_db::strip_array_keys($_event, 'cal_');
 		$rrule = calendar_rrule::event2rrule($event, false);
 		foreach ($rrule as $time)
diff --git a/calendar/inc/class.calendar_uiforms.inc.php b/calendar/inc/class.calendar_uiforms.inc.php
index 8658c4a9ad..30019e5c44 100644
--- a/calendar/inc/class.calendar_uiforms.inc.php
+++ b/calendar/inc/class.calendar_uiforms.inc.php
@@ -788,6 +788,8 @@ class calendar_uiforms extends calendar_ui
 									}
 								}
 							}
+							// check if we need to move the alarms, because they are relative
+							$this->bo->check_move_alarms($event, $old_event);
 						}
 					}
 				}
@@ -2764,22 +2766,7 @@ class calendar_uiforms extends calendar_ui
 				$recur_event = $this->bo->read($event['reference']);
 				$recur_event['recur_exception'][] = $d->format('ts');
 				// check if we need to move the alarms, because they are next on that exception
-				foreach($recur_event['alarm'] as $id => $alarm)
-				{
-					if ($alarm['time'] == $content['edit_single'] - $alarm['offset'])
-					{
-						$rrule = calendar_rrule::event2rrule($recur_event, true);
-						foreach ($rrule as $time)
-						{
-							if ($content['edit_single'] < $time->format('ts'))
-							{
-								$alarm['time'] = $time->format('ts') - $alarm['offset'];
-								$this->bo->save_alarm($event['reference'], $alarm);
-								break;
-							}
-						}
-					}
-				}
+				$this->bo->check_move_alarms($recur_event, null, $d);
 				unset($recur_event['start']); unset($recur_event['end']);	// no update necessary
 				unset($recur_event['alarm']);	// unsetting alarms too, as they cant be updated without start!
 				$this->bo->update($recur_event,true);	// no conflict check here
@@ -2805,6 +2792,10 @@ class calendar_uiforms extends calendar_ui
 			// stop it & create a new one.
 			$this->_break_recurring($event, $old_event, $this->bo->date2ts($targetDateTime));
 		}
+		if(!$event['recur_type'])
+		{
+			$this->bo->check_move_alarms($event, $old_event);
+		}
 
 		// Drag a whole day to a time
 		if($durationT && $durationT != 'whole_day')