Found a working solution in another post (I switched from Chrome to the download manager in Internet Explorer).
"I have just experienced exactly this problem, and have now found the solution.
The problem comes about when downloading an ISO from Microsoft which appears to complete successfully, but in fact is only a partial download.
When downloading an ISO from the MS website, instead of using the 'web browser' download option it is better to use the 'Download Manager' option. This ensures a complete download.
As soon as I did this the installation went ahead successfully."
Strange that MS does not have an MD5 check option.