I noticed that Macrium Reflect Free had stared to fail on scheduled backups and in fact was unable to connect to my NAS nor could file explorer, both using the server name. Connection could be made using the IP address. I could see the NAS as a media device but not as a network device in file explorer. To simplify things I uninstalled MediaMonkey and suddenly all was back to normal with the NAS showing up in the left hand pane of file explorer and Reflect happily backing up. I have no real idea of the cause of the problem, whether it was Windows or MediaMonkey or maybe any additional media programme but it might be something to check if anybody is having problems reaching a NAS using its share name.