I have a Windows Surface with Windows 8.1 Preview. I learned that if I installed Windows 8.1 RTM that I would not be able to keep my programs and setting without reinstalling everything. This was not acceptable so I began to find an alternative. After three days of trial and error here is what I learned.
• You need ISO image of Windows 8.1 RTM
• 1 USB Thumb Drive 4 GB or larger
• Rufus http://rufus.akeo.ie/
All the web nonsense about editing ISO images is just unnecessary and a waste of time.
Create bootable drive per instructions at this website ( http://www.eightforums.com/tutorials/15458-uefi-bootable-usb-flash-drive-create-windows.html ) but here are additional things that I encountered trying the procedure. (Remember Surface is UEFI computer select your computer type on line for Partition Scheme.)
The first time I tried this it did not work. My drive did not format correctly and Windows Explorer could no longer see the drive. Don’t panic. Go to Disk Manager in Windows and you will see the drive. Just format it with FAT32 and then you can try again.
My second attempt in creating a bootable USB device was successful. Since the USB image is just files and not an ISO Image then it was easy to edit the cversion.ini file as instructed here. http://news.softpedia.com/news/How-to-Upgrade-from-Windows-8-1-Preview-to-RTM-Guide-379950.shtml Ignore rest of this post as it is unnecessary.
Once the USB drive was ready, boot Surface or whatever computer that you have and insert drive into USB port. Use Explorer and double click on Setup.exe. It is not necessary to boot from UBS drive to run Upgrade. Enter product key. Eventually—if you edited cversion.ini correctly—you will be offered three upgrade options on Choose what to keep screen:
• Windows settings, personal files, and apps
• Just personal files
Of course the whole purpose of this blog is to get the option to keep Windows settings, personal files, and apps. Just follow any remaining prompts and you will have a happy computer upgraded from Windows 8.1 Preview to 8.1 RTM without reinstalling a single thing.