OK, I think I’ve got it figured out. If your PC started on Windows 7 and was then upgraded to Windows 8 (and 8.1 and the Update), it will probably be beneficial to take a step back (or forward) into a clean Windows 8.1 installation to properly prep your machine for the upgrade to Windows 10. I confirmed the following items for myself today on both of my remaining “problem PCs” (both were laptops that started out with Windows 7 pre-installed by Lenovo before they were shipped to me, and both had been upgraded to Windows 8 and 8.1 after that):
- Plucking keys from an existing 8.1 install provides the necessary permission to perform a clean install of the OS on the PC, even if that PC was only upgraded from its predecessor OS. The line labeled “Microsoft Windows NT Currentversion Win8” in SIW Pro turned out to be the key that worked for me for those machines, when I performed those installs (for each machine, it may actually have been the Windows 8 key that preceded the 8.1 and Update installs).
- Both had 128 GB OCZ SATA SDDs that had been the system and boot drive before I performed the clean install of 8.1, but I turned to a newer, faster, and bigger Plextor PX-256M5M mSATA for those duties on the clean re-install. [Note: those drives had already been installed on these PCs for some time, but I had never performed a clean install or cloned the original OCZ drives onto their Plextor companions.]
- The media builder for Windows 8.1 lives on a web page whose URL ends with “Windows-8/create-reset-refresh-media.” It worked like a charm, and enabled me to wipe the SSDs, and convert the old sys/boot drive to a data drive only, and create a default disk layout on the Plextor with a 300 MB Recovery partition at the head, followed by a 100 MB EFI System Partition, a 237.5 GB NTFS partition with the Boot, Page File, Crash Dump, and Primary Partition attributes. Windows 10 added a 460 MB Recovery Partition at the end of that structure during the upgrade install.
- After installing Windows 8.1, Windows Update asked me if I’d like to upgrade to Windows 10 immediately after the first login to the re-installed system. After I answered that query in the affirmative, I waited to see what would happen. At first, the PC sat and did nothing for a couple of minutes, but then it began downloading the files for the upgrade. Once that download was complete, it launched into the Windows 10 install process, and completed that installation. Gone was the delay for the 120 Updates that I’d found myself applying during my earlier rebuild attempts. Looks like Microsoft has made it possible to skip that busy work, but you must leave Windows Update alone and wait for the Win10 Upgrade download to complete. My earlier error, apparently, was to select the “Show other available upgrades” and wander away from the shortcut that MS makes available, if you have the patience to wait for it to get to work. Also gone were the earlier problems that caused the second boot in the upgrade install process to fail with a missing OS or unavailable boot drive error (the former bit me on the T520, while the latter gnawed my ankles on the X220 Tablet). It looks like the reformatting of the boot drive — or the selection of a different boot/sys device — forestalled that icky problem, which required wiping the affected boot/sys drive, and reapplying a system image, to correct.
I still had to rebuild my desktop environment to restore all of my applications and utilities to the Windows 10 environment. But it looks like I finally got the upgrade process to behave, essentially by figuring out how to go from a clean install of 8.1 directly into an upgrade to 10. Figuring things out took longer than anything else, and involved substantial trial and error on my part. Hopefully, my readers can benefit indirectly from the time and effort involved, and save themselves potential grief by avoiding the potential pitfalls that threatened to swallow me whole, and sucked substantial time and effort out of me before I tore myself loose. Live and learn, my friends, live and learn!
I’ve got two machines left to upgrade now, and then I’ll be done: my personal production desktop, and my wife’s everyday PC. If the straight-up upgrade fails, hers will be a piece of cake to rebuild after the clean-8.1 –> Win10 upgrade sequence I’ve described here is complete. Secunia PSI reports only 28 applications installed on that machine. Mine, however, is another beast entirely: Secunia PSI reports 87 applications installed, and I know I’ve got at 40 or more other tools on that machine that PSI doesn’t monitor at all. My disk layout appears to reflect a clean 8.1 install already in place, but with Windows, you never know what’s going to happen until you try, after which you can only hope you will interpret the results correctly. My total so far for Windows 10 clean installs is 6, all of which were totally successful; my total so far for Windows 10 upgrade installs is 9, of which 5 were failures and 4 successes (but 3 failures were on the same laptop that got me started on this whole adventure in the first place, the Lenovo X220 Tablet).