Delete Backup Set (Expire) not possible - Server Application Error

Hi,

i have the trial installation installed and migrated my old BE 2012 server.

After some testing, everything looks fine, but i am not able to delete some of the old Disk Storage based data.

I can select some Backup Sets, i can expire these sets, but they are not removed.

If i try to catalog the BS i receive a error message.

Server Application Error

Object reference not set to an instance of an object.

Server stack trace:
   at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)
   at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
   at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
   at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

Exception rethrown at [0]:
   at BackupExec.UI.Model.Connection.EndPerformCatalogImage(IAsyncResult asyncResult)
   at BackupExec.UI.ViewModel.BackupSetCommands.cmdCatalogBackupSet_Executed(Object sender, WPFCommand wpfCommand)

any idea?