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Can I edit the registry on windows.old using regedit on a fresh install of windows 10?

Oct 7, 2018
Hey folks, so I went ahead and borked my computer by changing a couple of things in the registry. (Specifically, I stupidly followed LeetLaurence's advice on this thread: http://www.tomshardware.co.uk/answers/id-1792156/secondary-harddrive-question.html?_ga=2.83839696.774278065.1538950706-1437403924.1534264608

I had no backup, no restore point, command prompt wouldn't open, couldn't open regedit to revert my changes, nothing. I resigned myself to doing a fresh install of Windows 10.

Now that that's done, I realise that there's a lot about the fresh install that simply won't work, so I'm wondering, is it possible for me to use regedit from the new install of Windows 10 to fix the changes to the registry in windows.old? And then reinstate Windows.old and remove the new install of Windows?

I hope I've explained myself well enough, but let me know if there's anything I can clarify!


Good grief that was a bad post and series of steps.
However...the very first line in there: P.S: Back up your registry before doing this

In answer to your question..I do not think there is a way to edit that Registry from your old OS.
Or apply that old Registry to a new install

Math Geek

you're better off working with the new install and making the few changes you wish to make there. of course back-up before you start and as you go along.

no reason to mess with the old install anymore as you'll be bringing with it any old issues that were there or that may have come about after messing it up when you did.

what changes are you trying to make?? perhaps there is an easier way to go about it??

also note that thread is from 2013 and is not even related to win 10. not a good idea to use old ideas on a much newer OS. but then you know that now......



That reg edit wasn't a good idea back then.
If he had read the rest of the comments, mine included...he probably would not have gone down that road.

Math Geek

folks ask this all the time when the obvious answer is simply to point the installer to the desired location as you install things. ....

takes more time to try and change the OS and fight the issues than it takes to simply point installers as you go. do it once for steam/origin and so on and no problems ever......
Yes, there is a way to access/edit registry from another windows installation.

Open Registry Editor,
Click on Menu File/Load Hive and point to registry file, you want to operate with.
Registry hive files are located in windows\system32\config and \users\yourusername\ntuser.dat .

When you're finished with editing, click File/Unload Hive.


Jul 18, 2017
Did you follow his steps and make a registry backup? Its the very first thing Leet stated to do his the steps...

With a backup, You do not need to be able to open regedit to restore the backup. Just double click on the reg backup file and it will automatically insert it back into registry. Then reboot the PC.

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