Perhaps it has something to do with the available space on the disk drive where Windows is installed?
After downloading the preview build from PC settings on my VM (which took almost two hours by the way), and hitting "install now", there was about a five minute pause before a dialog box popped up with a title that translates from Chinese as "Windows needs your help" and mentions that l will need to free up 4.9 GB of disk space on the C: (virtual) to allow the OS to install the new version.
After closing this box the installation continued, but as I had to turn the host computer off as I was going to bed, I put the VM (specific details in my previous post) in a "suspended" state with the update still appearing to be installed. No error code or message appeared at the time.
Has anyone who had this or any similar experience ever got the installation to succeed?