If you disconnect from the internet while using it, it will continue to work for up to an hour before your session expires and you lose access to your files. It requires internet as it authenticates you through the WD servers. You cannot use the My Cloud without internet access. You can access the My Cloud using Windows File Explorer or Mac Finder. If you don’t want to use the WD software, then don’t. The USB port on the My Cloud is host mode only, meaning you can only attach external USB drives too it. No you cannot reformat and use the My Cloud as a plain dumb external USB hard drive.
