What is the specific error message or dialog box that pops up indicating access is refused?
Have you previously used a different My Cloud Dashboard created user name/password to access the My Cloud on those computers that currently have trouble accessing the My Cloud? If so you may be experiencing a Windows limitation where you can only use one set of user credentials to access a NAS device. The workaround is to disconnect any mapped drives and clear out any My Cloud entries in the Windows Credentials Manager on the problematic machines.
