As reported on Neowin forum , after upgrading to Windows 8.1 many users have seen the disappearance of the reset function of the computer introduced by Microsoft in Windows 8, one that allows you to reset the state of the system to the factory settings without deleting data or applications (those in the Windows Store), so to speak. This problem is due to the fact that the digital version of Windows 8.1, downloaded from the Windows Store, ESD does not include files that are used to restore the system.
To restore these files, the user is prompted to insert the DVD into your computer or USB stick installation of Windows 8.1, which naturally supports are not in the availability of those who have downloaded the OS from the Windows Store. So how to fix it?
Apparently, the solution to this annoying problem is to download the ISO trial of Windows 8.1 Enterprise (32-bit or 64, depending on the copy of Windows 8.1 installed on your PC), mount the image and extract the file install.wim contained in it in the folder C: Win8(folder to be created).
Next, you must open the command prompt with administrator privileges and give the command reagentc.exe / setosimage / path C: Win8 / target c: Windows / Index 1, which should put the situation right.
To test the correct operation of the fix, just reboot the computer and try to start the system reset: if everything went the right way, you are not prompted to enter the installation media of Windows 8.1 and start the recovery process .