Problem after VirtualBox upgrade – Network & USB

After upgrade my VirtualBox from version 5.0.18 to version 5.0.20, both network and USB cannot work anymore,

1, Network issue, the virtual instance cannot start at all.

It reads
Failed to open/create the internal network 'HostInterfaceNetworking-VirtualBox Host - Only Ethernet Adapter #3'
(VERR_INTNET_IF_NOT_FOUND).
Failed to attach the network LUN
(VERR_INTNET_FLT_IF_NOT_FOUND).

Result Code: E_FAIL (0x80004005)
Component: ConsoleWrap
Interface: IConsol {872da645-4a9b-1727-bee2-5585105b9eed}

Resolved this issue by below method,

VirtualBox NDIS6 Bridged Networking Driver => unchecked status, as below pic shows,

VirtualBox NDIS6 Bridged Networking Driver => unchecked status, changed to checked status, as below pic shows,

2, USB issue:
Failed to attach the USB device OMNIKEY Smart Card Reader USB [0520] to the virtual machine Ubuntu.

USB device 'OMNIKEY Smart Card Reader USB' with UUID {a365e68f-a9a6-42c5-81c6-27fdf15425be} is busy with a previous request. Please try again later.

Result Code: E_INVALIDARG (0x80070057)
Component: HostUSBDeviceWrap
Interface: IHostUSBDevice {c19073dd-cc7b-431b-98b2-951fda8eab89}
Callee: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}

Refer to the reference link 3, it seems below procedure works for me,
1) First of all open regedit and navigate to HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Control > Class > {36­FC9E60-C465-11CF-8056-44455354­0000}
After you need to delete UpperFilters reg key from the right side.
2) Reboot your computer.
3) Now connect the USB device to your computer and open VirtualBox.
4) From the list select the virtual machine and from top open Settings and go to "USB" menu.
5) Now at right side press on "USB plus" green button and select USB device. Press on OK button and start the virtual machine.
6) Now disconnect USB device. Turn off the virtual machine and completely close VirtualBox.
7) Now connect the USB device and start virtual machine again.
If you are doing right then, USB device should work on your virtual machine.

Reference Link:
1, https://www.virtualbox.org/ticket/3033#comment:30
2, https://forums.virtualbox.org/viewtopic.php?f=2&t=64029
3, http://www.cyberprogrammers.net/2015/04/how-to-fix-usb-device-is-busy-with.html