The launch of Windows 8.1 on Thursday has not been completely trouble free. We have already reported that Microsoft has pulled the Windows RT 8.1 update for unknown reasons. Now there's word that some people who updated from Windows 8 to Windows 8.1 no longer have any refresh or reset options.
The issue was first reported on McAkins Online, and it affects people who bought and installed a retail copy of Windows 8 on their PC, either electronically from Windows.com or from a retail DVD disc or ISO image. In very simple terms, installing Windows 8 creates a ESD file that allows users to refresh or reset their PC. Installing the digital download version of Windows 8.1 does not provide a new ESD file, and as such, the ability to refresh or reset the OS after it is installed is eliminated.
Neowin asked Microsoft about this issue and the company sent over word that there are two situations where users will need some kind of media (an ISO burned to a disc or USB Flash drive) to enable refresh or refresh: "OEM devices without W8 PBR (very few)" and "Users that installed via DVD." Microsoft added, "For Windows 8.1, users that upgraded to Windows 8 via online download (ESD), will need media when updating to Windows 8.1. Also, users that upgraded to Windows 8 via DVD then updated to 8.1, they will need to use their Windows 8 DVD to go back to Windows 8 if needed."
However, according to McAkins Online, adding a Windows 8 disc or ISO image in a PC drive after updating to Windows 8.1 will not work, as users will see the error message above. Since there was no install media provided by the Windows 8.1 upgrade, users cannot refresh or reset their PC.
While Microsoft has not provided an ISO image for the Windows 8.1 update from the Windows Store, McAkins Online points out that there is a 90 day free trial version of Windows 8.1 Enterprise with an ISO that anyone can download. The site offers a fairly complicated workaround to using those ISO files so that Windows 8.1 users can enable the refresh and reset options.
Source: McAkins Online