

The actual problem in your case the saved state of the VM does actually not contain the information about the USB 2.0 controller because it was not available when you started the VM - you got the warning and just ignored it. If there is a saved state of the VM available, we do not allow to start the VM if such a special feature is missing because in that case the hardware of the guest would change during restore which is not possible (the USB 2.0 controller is not hot-plug-able). The intention is to allow the user to start a VM but show a big fat warning if he enabled a feature which is only available from the extension pack (in your case USB 2.0).
