Preview stopped working

Hi there,

all of a sudden I am not able to preview my work anymore using the preview function in Storyline 3. i get an error message when I try to preview something. It's worked perfectly all the time and now all of a sudden I'm getting this error.

I started a new project and inserted all of slides from the project it occured first and then tried to preview this one and wanted to save and replace it but as you can see this didnt work. The recorded video as well as the code it gave me are attached.

Hope a hero can help.

Best regards.

<?xml version="1.0" encoding="utf-16"?>
<ErrorReport xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <FirstName>Mona</FirstName>
  <LastName>Idemudia</LastName>
  <EmailAddress>mona.idemudia@freudenberg-filter.com</EmailAddress>
  <UserId />
  <MachineName>WH2L8024</MachineName>
  <HardwareId>TV93U-6MVHY-UPME0-DRP13-FWY1A</HardwareId>
  <Message>Sequence contains no matching element</Message>
  <StackTrace>   at System.Linq.Enumerable.First[TSource](IEnumerable`1 source, Func`2 predicate)
   at b0o.a.get_Location()
   at b0o.get_Location()
   at Articulate.Design.TabOrder.TabOrderShapeComparer.a(Shape A_0, Shape A_1)
   at Articulate.Design.TabOrder.TabOrderShapeComparer.Compare(TabOrderShape tabOrderShapeA, TabOrderShape tabOrderShapeB)
   at System.Linq.EnumerableSorter`2.CompareKeys(Int32 index1, Int32 index2)
   at System.Linq.EnumerableSorter`1.QuickSort(Int32[] map, Int32 left, Int32 right)
   at System.Linq.EnumerableSorter`1.Sort(TElement[] elements, Int32 count)
   at System.Linq.OrderedEnumerable`1.&lt;GetEnumerator&gt;d__1.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Articulate.Design.TabOrder.DefaultTabOrderCalculator.a(IEnumerable`1 A_0)
   at Articulate.Design.TabOrder.DefaultTabOrderCalculator.GetDefaultTabOrder(TabOrderShapeCollection shapes)
   at Articulate.Design.TabOrder.TabOrderShapeSorter.GetOrderedShapes(TabOrderShapeCollection shapes, TabOrderMode mode)
   at Articulate.Design.TabOrder.TabOrderShapeSorter.GetOrderedShapes(TabOrderShapeGatherer shapeGatherer, TabOrderModeProcessor modeProcessor, ITabOrderedObjectContainer shapeContainer)
   at Articulate.Storyline.Slides.exSlideBase.AssignTabOrderForPublish()
   at Articulate.Player.PlayerContentPublisher.CreateSlideObject(IPlayerSlide slide, bwISlideContainer sceneobj)
   at Articulate.Player.PlayerContentPublisher.CreateBridgewaterSlide(PlayerWriterSettings settings, IPlayerSlide slide, bwISlideContainer sceneobj)
   at Articulate.Player.PlayerContentPublisher.CreateContentScenes(PlayerWriterSettings settings, IPlayerContentProvider contentProvider)
   at Articulate.Player.PlayerWriter.WriteContent(IPlayerContentProvider contentProvider, Nullable`1 merged)
   at Articulate.Player.PlayerWriter.Write(IPlayerContentProvider contentProvider)
   at Articulate.Design.Publish.TargetContext.PublishBackgroundWorker.OnDoWork(DoWorkEventArgs e)
   at Articulate.ComponentModel.STABackgroundWorker.a(Object A_0)</StackTrace>
</ErrorReport>