Okay, I've been trying to think this through for hours. Tenforums has step-by-step screens of the 'upgrade' using either the media tool or Windows update (icon click in system tray). Then it also has step-by-step screens of the 'clean install', which you can only do AFTER the update. (Sorry, I didn't see equivalents here in BC, so am using their links.)
- The installer doesn't want your input.
- It instead wants to search your old version of Windows for the product key,
- so you aren't allowed to furnish one:
- you are instead required to UPGRADE IN PLACE, the Win10 atop your current (even if you keep nothing).
- Any key requested is a Windows 10 key, as the installer also handles Win10 purchased installations.
- You won't have such a key prior to upgrading in place. So you're never asked for your earlier-version key. Once you update to Windows 10 inplace, you have no key to specify still, as now the Win10 key replaces your old one, and is still embedded in the now-Win10, updated installation.
So I get the following conclusions:
1. Unlike with us Insiders, the official Win10 installation really wipes out the prior version, since you're only allowed to do an inplace upgrade. Win10 terms in the lifecycle sheet are tied to 'OEM support' and mandatory updates. These restrictions are not in prior OS versions. So you just replaced your better old license, with a more restricted license.
2. Potentially, if you wanted UEFI, the installer changes all partitions for clean install, so effectively wrecks your ability to restore your prior version: so the '30 day' rollback provision, is nullified.
3. You can't dual boot with your older version and the Win10: for how can you restore your old version, even if you did a non-UEFI clean install of Win10 to a new partition? You effectively replaced your old version's license with the Win10 license due to mandatory update in place.
4. The only way to undo this is to clone your hard drive prior to install, then clone the clone back to your drive post-install. I don't see how the Windows.old file will work anymore.
What am I missing here?
Edited by brainout, 30 July 2015 - 11:46 PM.