Upgrading from Windows 8.1 Preview to Windows 8.1 RTM and keeping your settings and apps intact is possible. Just follow this small guide:
- Download a Windows 8.1 RTM ISO and any ISO explorer, such as trial versions of Power ISO or UltraISO.
- Browse the content of your Windows 8.1 ISO with Power ISO or UltraISO and go to the “sources” folder and look for the cversion.ini file.
- Open the .ini file with a text editor like Notepad or Wordpad.
- Modify both entries from 9458 to 9431. See the SCREENSHOT.
- Save the ISO by going to the file menu and clicking "Save".
- Burn the ISO to a DVD USB stick and install Windows 8.1 RTM OS. The installer will now correctly determine the OS version you’re upgrading from and you will be allowed to keep settings and apps.
Need further help? Post in the comments.