Windows 10 Upgrade: Can I keep my Old Windows Install?

Dennis Faas's picture

Infopackets Reader Lisa A. writes:

" Dear Dennis,

Thanks for the great website and newsletter. I have a question regarding upgrading to Windows 10. I have a machine with Windows 7 and another with Windows 8, both of which have reserved the free upgrade to Windows 10. My question is this: if I upgrade to Windows 10, can I keep my old version of Windows on the same machine and boot from it? "

My response:

If you are performing an in-place upgrade of Windows 10, then you will not have a choice as to which operating system you want to boot into. That's because the in-place upgrade to Windows 10 will effectively replace your old version of Windows, porting your programs and user data over to the new Windows 10 system. The majority of users will be performing an in-place upgrade to Windows 10, which is downloaded via Windows Update.

That said, it is possible to keep your old Windows installation alive and kicking if you dual boot Windows 10, or convert your existing Windows installation into a virtual machine. I'll describe that next.

Dual Boot Windows 10 and Keep Your Previous Windows Install

If you want to keep your old version of Windows using a dual boot (otherwise known as a 'multiboot'), then you would have to create a new hard drive partition for Windows 10 on your existing drive, or use a second hard drive inside the same machine.

You will then need to obtain the Windows 10 .ISO when it becomes available and burn it to DVD, or create a bootable USB drive. Once the bootable DVD or USB is created, you would reboot your computer and boot from the newly created media, then choose an Advanced Windows installation, and select an empty partition for Windows 10. That will effectively tell the Windows 10 installer that you are creating a dual boot system.

Please note that dual boot or multiboot operating systems can become overly complicated, especially later on. For example, if you install Windows 10 on a second hard drive and your main boot drive fails (which contains your old copy of Windows), then you will not be able to boot into Windows 10. Also, removing or repairing a corrupted dual boot is not easy. As such, I do not recommend you dual boot Windows 10 as it is overly complicated and there is not a lot of support for such configurations using third-party apps. Instead, I suggest you virtualize your machine, described next.

Create a Virtual Machine and Keep Previous Windows Install

Alternatively you can convert your existing Windows 7 or 8 into a virtual machine and run your old version of Windows inside of your newly installed Windows 10. You can then access your old version of Windows as if it were a separate machine on the network using Windows Remote Desktop (for example). You can even network your old hard drive, and access your old computer data, just as if it were a real computer.

Since you can run both the virtual machine and the newly installed Windows 10 at the same time, I believe this is the preferred method because you won't have to keep rebooting to access one or the other. The down side to going this route is that you need at least 4GB of RAM (8GB recommended) and a quad core processor to run a virtual machine, otherwise it will be too slow to be useful.

Additional Support: from Dennis

If you need help converting your existing Windows machine into a virtual machine, you may contact me for support. I'll use remote desktop assistance to connect with you 1-on-1 and examine your existing setup, and implement the appropriate measures to ensure that you can keep your existing Windows and use it on the new Windows 10 system.

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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Phil's picture

Great "treetops" article, but I'd appreciate a link to a ground-level *how to* piece on making a Win 7 Pro SP1 setup into a virtual machine, and then running it from inside Win 10 the way you describe!

Are there any assurances that any software that runs under Win 7 will run under Win 10?

As to hardware. my older laptop's motherboard Intel graphics circuit is flagged by the "Get Win 10" icon as being troublesome, and my desktop's old hp 2035 LCD display gets a similar warning (but at least that could be replaced or perhaps run using a generic display driver).

giingy's picture

Yes. I'd very much like to hear the specifics on how you would implement this, including software recommendations.

I have done a p2v conversion in the past (I can't remember the details) but I do remember it being a bit of a pain, and it didn't seem as reliable as I'd hoped, so I'd like to hear your thoughts and experiences on it.

Tessman_Ian's picture

What VM package do you recommend and/or use?

ruellej's picture alternative to the dual boot is to install a second HD for win 10 installation and then set up the dual boot in the BIOS. Most new machines have a F-key option to enter the BIOS dual boot menu at start up.

To make the operation simple, (assuming one is not using an ISO to install win 10) I would suggest cloning the current hard drive and install win 10 on the clone.

keffdoak's picture

Another way to keep your Windows 7 system, although more cumbersome, is to make a disk image of it with Dennis' favorite product, Acronis True Home. You can install Win 10, also make a disk image of that system, and then overwrite it with Win 7 whenever you wish. I have several images that I swap out for different uses. It's a pain having to update (patch) all of them, and I have to be careful to back each one up before I restore another, but it works.