How to Clean Install Windows 10 using Windows 7, 8 License

Dennis Faas's picture

Infopackets Reader Meagan S. writes:

" Dear Dennis,

Thanks for your coverage on Windows 10. I plan to upgrade to Windows 10 but I prefer to do a clean install, rather than in-place upgrade. I say this because I would much rather start from a clean slate, rather than worry that bugs from my previous Windows install might port over onto my new Windows 10 upgrade. So my question is: can I do a clean install of Windows 10 using a Windows 7 or 8 license? If I download the Windows 10 ISO and format my hard drive, how will Microsoft know that I am in fact upgrading to Windows 10, and therefore receive the free upgrade without having to pay for a Windows 10 license? "

My response:

This is a good question.

Rumor has it that in order to do a clean install -and- retain your free license to Windows 10, you must first install Windows 10 using an in-place upgrade; this is done from within an existing Windows desktop environment via "Get Windows 10 app". After that, you can then do a clean install using a Windows 10 DVD as many times as you want.

The license for Windows 10 will be valid for the life of the device, and any subsequent clean installs will automatically register with Microsoft without requiring you to enter a serial number ever again. The free Windows 10 license is valid providing that you don't make any major hardware changes (such as a new motherboard, which technically constitutes a new computer). A new hard drive, for example, is not a major hardware change. Therefore the free Windows 10 license is tied to specific hardware (such as motherboard, CPU, RAM, etc).

What if the Get Windows 10 App is not in my Tray bar?

In order for the "Get Windows 10 app" to appear in the Windows tray bar, a number of prerequisites must be met. Please refer to this article for more info.

Why can't I install Windows 10 using an ISO and get a free upgrade?

I'm guessing that the reason has to do with the fact that a Windows license can only be registered from within a fully installed Windows environment using a valid Internet connection (or telephone to Microsoft); if you run the Windows 10 install media, then you are not running a fully installed Windows environment (and without having gone through the registration process). Therefore, you must use the "Get Windows 10 app" to perform an in-place install, first. After that you can do a clean install once your device is registered as having a valid free Windows 10 license.

Other Questions Related to Windows 10 Upgrade

We've recently answered more questions related to Windows 10, including in-place upgrades and clean installs. Feel free to read more:

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About the author: Dennis Faas is the owner and operator of With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.

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alan.cameron_4852's picture

Your article is quite clear you have to have done a in-place upgrade to get the Windows 10 Licence free. What you have not said is the arrangements for those of us who are testing Windows 10.
Have you any information about that case?

Dennis Faas's picture

If you want to test Windows 10 then I suggest downloading the .ISO when it becomes available, then run a virtual machine (or use a spare computer).

stooobeee's picture

If the Win 10 In-Place installation fails, it cannot register Win 10. I suspect a reinstallation of Win 7 or a Reset or Refresh of Win 8.1 would be in order before Win 10 will succeed.

Dennis Faas's picture

You should backup using a disk image first, then attempt the Windows 10 in-place installation. If it fails, you have two choices: 1) revert the disk image backup, or 2) install windows fresh and download all the updates, and eventually get to the point where you can install Windows 10 again and give it another go.

f58tammy's picture

Hello I hope this will help someone. First let me apologize to Chip if this is longer than his article.

The way Microsoft explained the new System upgrade/install was this (I watched the live program) first it takes the old system and places it on another section of the drive. Then it installs the new OS (essentially a clean install) where the old system was. Then it put in all the necessary drivers and the user files and programs, from the old system. The old system will show up in 3 folders $SysReset, RecoveryImage and Windows.old. These are used in the recovery process.

Now in the Update & security section of Settings you will find the Recovery section. You have 3 different options Reset this PC, Go back to a earlier build and Advance startup. Lets start with Reset this PC. This will in essence get you a clean install.

You will find two options in Reset this PC (both options will renew you licenses and activate the new OS). Either option will create a new Windows.old deleting the previous system that was in the folder. So if you upgraded from a Windows 7 system you won't be able to go back to it in the Go back to a earlier build option. If you have not made a disk image of your Windows 7 and want one, you should use the Go back to a earlier build option first, this will reinstall your Windows 7 system. Make your back-up disk system image, and then redo the Windows 10 upgrade. Keeping in mind if you make hardware changes i.e. Motherboard/CPU you will need to reactivate your system.

The first is "keep my files" this option will put a fresh copy Windows 10 on your dive replacing the old OS, saving your user files and settings and reinstalling them. You will have reinstall third party programs. Any programs you have installed by disk or downloaded and installed. Your Windows Store Apps should be reinstalled.

The second is "Remove everything" This will Delete all the files on the system partition/drive. It then will put a fresh copy of Windows 10 (in essence making a clean install of Windows 10). Keep in mind you will have to copy all your user files back into the fresh installation and reinstall all you programs.

I basically explained the Go back to an earlier build option earlier, that leaves the Advance startup options, this is were you would use a ISO or backup image to to replace the system on the drive. If you use a ISO you will need the appropriate numbers in order to activate the system.

Now to my opinion, there has been a lot of discussion about getting the ISO and doing a clean install. For those who want to pay $119.00 for the numbers to activate the ISO, and spend the time replacing files and programs Go for it.

One thing to consider Microsoft is working on a new pricing structure for there OS's where it will be a pay as you go type of pricing plane were there will be a monthly/yearly fee for updates and system changes, something like that they are using for the Microsoft Office program. That is why Microsoft has stated they will be giving updates and new systems for the life of the computer(meaning no hardware changes)for the Windows 10 upgrade, this was stated on the above mentioned program

If you are having problems with your current system, I would suggest doing the upgrade and see if Windows 10 corrects the problem or Windows Defender finds the virus or malware and quarantines it. You might try using the compatibility option if it is a program having/creating the problem. If your still having problems then you can resort to the recovery options I have mentioned.

If your system has no problems then I would definitely suggest the upgrade and try it before making a decision on how you want to proceed.

I am Tammy Thomas the first program I used was FORTRAN IV, the first Windows computer was 2000. I have been using technical Previews starting with Windows 7. I had one problem with the one Windows 10 preview updates, it was a activation problem (Microsoft had a server problem) I used the Go back to a earlier build option with no problems what so ever I even had my sticky notes on my desktop. I re did the upgrade after the the problem was fixed. This last update on my comp took less than 25min from restart to desktop with not having to do anything to complete the process.

Again I truly hope this information will be useful for someone, I have not meant any disrespect to anyone.

mcleod55's picture

Every time I try to do the Windows 10 update I get the following message. "We couldn't update the system reserved partition".
My Windows 7 is on SSD with 62.2 GB free space. The reserved partition is 99.9 mb with 65.6 mb free space. How can I correct to allow update?