Will it be possible to revert to Windows 8 after installing Windows 10 (not preview)?

Is there any reason that one could not revert to a previous OS (e.g. from a disk image) after installing the full release of Windows 10? It might be possible for MS to repartition the disk during installation, or to install a new file system that could not be read by the WinPE or Linux restore media.

Has anyone had experience, at least with the preview version, in doing a full restore? This is not exactly what is asked in Uninstall Windows 10 Tech Preview (reverting back to Windows 8.1), Uninstall Windows 10 Tech Preview... the question concerns a full disk restore.

DrMoishe Pippik

Posted 2015-06-04T17:54:16.397

Reputation: 13 291

Not reverting using MS recovery media, but with a full HD restore. Please read before replying. – DrMoishe Pippik – 2015-06-04T18:04:46.537

I did read; I don't see the difference between the two questions; It has never been possible to uninstall Windows X after you upgrade from Windows Y. Windows X has always replaced Windows Y with only Windows.old being used stored handle anything that isn't compatible with the new installation. This questions describes a possible solution, using that folder, don't really trust the instructions since it doesn't even address the registry.

– Ramhound – 2015-06-04T18:08:06.480

If a primary disk is restored from a previous image, e.g. one made with Acronis or Macrium Reflect, using the boot media created by those imaging tools, that is not the same as using the the Windows Recovery Media. Though in theory it should be possible to restore the exact image of the disk before update, the question posed is has MS made it impossible to access the disk from recovery media? – DrMoishe Pippik – 2015-06-04T18:19:07.243

I'm not sure I'm understanding the question. Can't you always restore a system from a disk image (the purpose of a disk image)? – fixer1234 – 2015-06-04T18:28:47.000

That is the question... MS has created a number of files systems, such as NTFS and exFAT, that at one time were not readable by Linux and other OS. MS has also added additional partitions for UEFI boot and for System Restore. Does Windows 10 introduce a new FS, or a new partition scheme, that might confound a full image restore? – DrMoishe Pippik – 2015-06-04T18:36:50.550

1Whilst you would almost certainly be able to restore the disk and run successfully, it is unlikely that the copy of Windows 8 will be correctly licensed and may well be treated as a pirate copy. The upgrade license is just that, I don't believe it will come with downgrade rights. The whole point is for MS to move as many people as possible to W10 and ditch W7/8. – Julian Knight – 2015-06-04T18:40:18.817

Windows Recovery Image is just WinRE. Its the samething that exists in the Recovery Partition. Windows Recovery Media is used if that partition is not accessible for some reason. – Ramhound – 2015-06-04T18:44:41.597

@DrMoishePippik - Your questions in your last comment are extremely broad. The features of Windows 10 are known. It introduces no new filesystem, no new partition scheme, what it does introduce easily researched. So how is this not a duplicate about uninstalling the preview version of Windows 10? – Ramhound – 2015-06-04T18:45:51.753

@JulianKnight - Windows 10 will be sold. Trying to worry about how the process will be different in July 2016 vs July 2015 just adds confusion. If Windows 10 is uninstalled, the license used to upgrade, literally cannot in my opionion be invalid. Unless I agree to have my license revoked Microsoft cannot simply, revoke it. – Ramhound – 2015-06-04T18:47:57.187

@Julian Knight, thanks, that answers the question... if you move it to an Answer, I'd accept it! – DrMoishe Pippik – 2015-06-04T18:49:37.510

@Ramhound. Sorry, I've been doing a lot of work on MS and other licensing recently and must respectfully disagree. Once upgraded, the old license is no longer valid. That is the contract between you and Microsoft, the cost of the upgrade if you will. There are lots of horrible details hidden in licenses. – Julian Knight – 2015-06-04T19:06:13.617

@DrMoishePippik: For argument's sake let us suppose Win10 does introduce a new FS and partition scheme (although we know it does not). You are talking about a full disk image, so why should the previous contents matter? The disk image when restored will restore not just the files but the previous partition scheme and FS as well. Your question really makes no sense. – Karan – 2015-06-04T19:57:06.710

@JulianKnight: "Once upgraded, the old license is no longer valid." - Isn't that true only for a simultaneous install? AFAIK it is still legal to uninstall the update, reinstall the old OS, activate, and use the update on another PC. So why should it not work the same way with Win10? – Karan – 2015-06-04T20:04:37.183

@Ramhound, this is off topic but have a correction. Windows xp users who upgraded from 98 or ME, were able to uninstall XP from add and remove programs menu ;-P

ref

– pun – 2015-06-04T22:19:56.477

@JulianKnight - I have asked you for this before. Where does it say this? I maintain that a license cannot be made invalid without some sort of agreement on my part, otherwise my agreements for that current license, is still valid. Microsoft CANNOT change a contract without consideration from both sides. – Ramhound – 2015-06-04T23:38:36.520

@Ramhound and my answer hasn't changed! Of course a license can be made invalid! Microsoft maintain a database of valid licenses and they set what is valid and what isn't - not the people who have "purchased" the software!! MS make licenses invalid every day. Your license is checked every time you connect to Windows Update & that is set to get a LOT tighter in the next set of changes they are about to announce. Another reason they want everyone on W10. – Julian Knight – 2015-06-04T23:47:34.910

@JulianKnight Except the 10 upgrade explicitly lets you go back to your previous version within 30 days if you don't like 10. – Andy – 2015-08-31T21:46:16.577

Answers

-2

Whilst you would almost certainly be able to restore the disk and run successfully, it is unlikely that the copy of Windows 8 will be correctly licensed and may well be treated as a pirate copy. The upgrade license is just that, I don't believe it will come with downgrade rights. The whole point is for MS to move as many people as possible to W10 and ditch W7/8

Julian Knight

Posted 2015-06-04T17:54:16.397

Reputation: 13 389

3Any official word on that? I was under the impression the big version upgrades just generated a new key and ran happily. And with OEM copies at least, there's no reason the SLP keys in windows 8 would be deactivated. And you've often had the option to downgrade a windows 7 licence to 8. – Journeyman Geek – 2015-06-04T23:53:36.450

@JourneymanGeek - Downgrade rights are a little different then what I am talking about. – Ramhound – 2015-06-04T23:57:23.397

@JourneymanGeek, MS are playing things very close to their chests and haven't released official word as yet. OEM licenses are far more restrictive than most people think. That people use them incorrect is only because MS don't make something of it but they could, OEM licenses are assigned to an individual machine. What you can do and what you should do may be different. – Julian Knight – 2015-06-05T07:50:53.230

2Precisely. This isn't really an answer as is tho, its speculation in my opinion. I do know my OEM windows 7 install is getting an upgrade so... I'm not convinced this may be correct. – Journeyman Geek – 2015-06-05T07:59:43.397

For those naysayers and downvoters. MS have now clarified. Your previous license is subsumed into a W10 license and cannot be recovered. However, you will get limited and temporary downgrade rights but you MUST create a suitable recovery disk before upgrading.

– Julian Knight – 2015-07-25T16:46:12.723

Nothing in that link says your key is invalid should you choose to go back to your old version. What it says is someone unfortunately got their OEM key stolen (probably generated by a keygen and marked invalid). Note that the 30 thing seems to be technical, because if you wait that long 10 will automatically delete the windows.old folder that contains the previous version, which makes it impossible to go back. But i've not read anything from ms that says you'll not be licensed if you manage to go back anyway. – Andy – 2015-08-31T21:34:45.550

And FWIW, that OEM key silliness is why i build my own computer and buy a retail copy of windows. – Andy – 2015-08-31T21:35:57.793

@Andy – go try with your Windows licence, then come back and tell us the results. :) – miroxlav – 2015-08-31T22:07:00.307

Windows 10 uses NTFS as the file system , so using WinPE or Linux restore media should not be a problem, here is a screenshot of the W10 preview edition I have installed and will not be changed for the RTM of W10.

enter image description here

Moab

Posted 2015-06-04T17:54:16.397

Reputation: 54 203

Thanks, and what about the System and Recovery partitions? On my Win 8.1 PC, the primary drive has 1 GB NTFS System (Recovery), 256 MB FAT32(LBA) EFI System, 128 MB NTFS unnamed parition and ~700 GB NTFS main partition. Windows, I believe, creates the Recovery partition and possibly the EFI partition, as well as the main file partition. – DrMoishe Pippik – 2015-06-04T22:26:04.970

@DrMoishePippik - All those partitions will remain untouched? The only partition that will be touched is the system partition. – Ramhound – 2015-06-04T23:39:34.347

If other partitions are present during installation and you specifically point Windows setup to install on a particular partition, it will not touch any of the other partitions and will not create any other partition other then the system partition. Only on a blank hard drive will a Windows setup create additional partitions. – Moab – 2015-06-05T12:49:53.557