To eliminate the possibility that this is a Windows issue vs. a host/VBox issue, what happens you restore the guest from snapshot and roll back the virtualbox update? Be sure to roll back ALL VBox related packages to their previous version.
To eliminate the possibility that this is a Windows issue vs. a host/VBox issue, what happens you restore the guest from snapshot and roll back the virtualbox update? Be sure to roll back ALL VBox related packages to their previous version.