Go Back to the Previous Version of Windows in Windows 10  

Hello Cylliq, and welcome to Ten Forums. :)

Sometimes it can take quite some time to finish. As long as you have hard drive activity, it would be best to let it sit until finished.

I will be updating this later since I just saw not only the upgrade on a second custom build but a clean install the day before that being activated once the upgrade took place. Since the clean install is up and running strong and activated I can now revert the upgrade back in order to restore the dual boot with 7. I couldn't toss a temp install of 7 there since it's only a one drive system used remotely and for testing things keeping the main build isolated which also saw an upgrade replaced however.

Noting the time on today's date at 6:48pm est we'll see how long it takes on the fly! Should be ready by 7:30 at the latest I would assume.

UPDATE: No Go on the revert back to 7. Upon browsing the drive I didn't find any Windows.old folder which would normally have to removed. Will try again.

Hello olblindman, and welcome to Ten Forums. :)

It varies wildly from system to system based on if there were any issues, system specs, etc....

In a perfect situation without issues and a reasonably fast PC, it could take around 10-20 minutes.

As long as you have hard drive activity though, it's best to let it sit until finished to avoid possibly having to do a clean install.

You might wait at least another hour to see if you have any progress. If you don't still hear the drive clicking away by then, it may be time to consider a clean install if a restart doesn't help.

Well that's what I ended doing here alright but only when not finding the Windows.old folder now being nuked on the second clean install of 10 to the first of a now two drive system I knew that the 7 install could either be replaced and lose 10 off of the drive entirely or restore the original image made of 7 and put another clean install of 10 since moving the second primary to the front of a drive usually sees trouble like no more boot loader or BCD store!

And as I expected the move of the second primary back after the first 7 upgraded over primary was gone resulted in an unbootable drive. Funny how it takes so much longer to transfers the files I needed back on by way of a large usb flash drive then it takes to repartition and reOS a drive!

Some observations, I am not saying what I have experienced in my tests is how this always works but I can reproduce the behavior told below, have done both Option One and Option Two as told in this tutorial two times (four times altogether) now on the same hardware and the results are the same on each try.

The underlying previous Windows version in all four tests Windows 8.1 Pro N, clean installed and activated with a retail product key.

• Before restoring the previous Windows version, when Windows 10 was still in use and activated, I could not reuse the underlying Windows 8.1 Pro N retail key on another hardware getting the notification about the key being used on another PC.
• Restoring the previous Windows version, Option One took on this hardware both times almost 90 minutes, Option Two about 20 minutes.
• After reverting to previous Windows version, it was activated on all four tries as it had been before the upgrade.
• When the previous Windows 8.1 Pro N was restored, I tried to reuse this retail product key simply by uninstalling the key first with Software License Manager (command: slmgr /upk). This removes the Windows activation and it needs to be reactivated.
• Trying to reactivate Windows with the product key I had uninstalled after reverting to Windows 8.1 Pro N with Option One, the process had not "released" the underlying Windows 8.1 Pro N product key and the activation did not work, I was not able to activate Windows with that key. This was the same on both tries.
• Trying to reactivate Windows with the product key I had uninstalled after reverting to it with Option Two, the process had "released" the underlying Windows 8.1 Pro N product key and the activation was successful, I was able to activate Windows with that key. This was the same on both tries.

As I mentioned, I do not want to say this is how it always works. In fact I cannot understand what the method I used to revert to previous version of Windows has to do with releasing or not releasing the product key of the previous version. I tested this by first creating a system image when in Windows 10 and it was activated after the upgrade from 8.1, then restoring this image after each test run and starting from beginning, reverting to 8.1.

Kari

I think that will now only benefit those who only recently or will be upgrading to 10 since anyone who went for 10 back in July is no longer able to revert back but will need to see a full clean install of the older version. Many simply opt to wipe a drive clean once all files are backed up when not having any option to revert to the previous version.

At this point having run 10240 rtm since first out I know why some might want to revert from having seen the initial upgrade turn out faulty! That may just scare some away where they then simply want to go back to the prior they had on. But in some cases the rush to clean up the Windows.old and other temp install folders will prevent any reversion back. Those have to remain intact when first trying 10 out.

If I had upgraded a single drive system and had found 10 anything like 8 then I may have opted to revert back to see if I could get 7 going again but had planned a dual boot of both ahead of time automatically canceling that out. I had previously run one of the earlier builds and wanted to give 10 a good work out instead! So far so good!