Open Plugin-view "Ultrasound Support"
--> Remove all available ultrasound devices
--> Click "New Video Device"
--> Click "Add Video Device"
--> Click "Activate" then click "Deactivate"
Open Plugin-view "IGT Navigation Tool Manager"
--> Click on "Load"-Button next to "Whole Storage"
--> Cancel opened file dialog.
--> Close MitkWorkbench
--> Start MitkWorkbench again
--> Open Plugin-view "Ultrasound Support"
--> The last created ultrasound video device is not available due to the disturbed ultrasound persistence.