[Users] VM-List gone after upgrade to 3.4

Hi, today I upgraded from 3.3.4 to 3.4 aus discribed in the release notes. Then executed "engine-setup" which finished without error. Though I can see the running VMs in the according tab on each node (Hosts -> Node -> Tab: Virtual Machines) I don't see anything in the "Virtual Machines" tab (System-> Virtual Machines). It just keeps loading forever. So currently I cannot view any VM that just has been created or is stopped. Is this a bug or did I miss something? Cheers, Stefan