As indicated above see the Compilation of Windows 10 Methods, Steps and Solutions thread (first post in that thread) and ensure any Windows 10 computer that cannot see the My Cloud is properly configured. Pay particular attention to Windows 10 Specific Methods 1 through 5. There are a couple of settings in Windows 10 that need to be checked and possibly reconfigured.
Also disable any third party firewall or security/anti virus software as a troubleshooting step. It is possible that third party software is blocking proper communication to the My Cloud.
In general so long as your My Cloud is properly functioning, in the same IP address subnet range, and using the same Workgroup name as the computers on the local network those computers should be able to access the My Cloud. It those computers cannot, the problem is typically either on those computers or there may be a configuration problem with the local network master router.
