This issue occurred on Windows client with nxserver --shutdown, after trying to import any device to the client from the server.
This was not possible.

Steps to reproduce:
- On client Windows machine run ./nxserver --shutdown
- Connect to machine2
- Try to import a disk /usb device to client from machine2.

A possible workaround is:
- open windows console as administrator and run command:

net start nxservice

After a successful start, disk/usb sharing will be available in the client UI.