If you're a tech guy like me, and have had some fortunate and unfortunate experiences with Windows in the past, you know that it's important to always keep backups. And when it came to deciding to upgrade to Windows 10, I was skeptical at first, and the offer seemed too good to be true, but I still took it.
Because of my skepticism, I ensured that I would be able to rollback or reinstall my old version of Windows 7 without losing my files. Even though most of my content is online now, there are still many files I would hate to lose. Luckily, Windows 10 includes a new feature that will allow you to go back to your old version of Windows 7, 8 or 8.1. On the other hand, you are only able to do this a month after installing Windows 10. This means that once you install Windows 10, you have exactly one month to decide if you like it. If you don't, and a month has passed, you're out of luck, and you'll have to start fresh from a new Windows 7/8/8.1 clean install if you choose to go back. Why is this? I'm not sure, but there's a few possibilities. One could be simply that Windows doesn't want you to always have the opportunity for you to switch back, and they are praying that you will accept the process of change and start liking their new OS. Another reason could simply be hard drive space. Depending on the data you had on your old install before upgrading, your computer may have an additional 30 to 100 GB of useless space for redundancy, just in case you decide to go to your old version. And after that one month, that hard drive space could be eaten up pretty quick. So Windows may simply only give you one month to get rid of that space.
Now, let's say you still want to keep your old Windows version, even after a month. How would you do this? Let's find out!
Step 1: Locate the Old Version's Files
Under your C: drive, there should be a folder called "Windows.old". If you do not see it, you may have to enable hidden files, or disable "hide protected operating system files" to view it. Once you locate this file, either select it and press CTRL-X, or simply drag it to your desktop.
Step 2: Move the Folder to a Different Location
The next step is as simply as moving the folder to another location, such as the desktop. You're pretty much done!
Step 3: Ensure Windows 10 Doesn't Detect the Older Version
Open the Start menu and search "Reset this PC", and select the first option. You will be brought to a window that will give you several options. The second option should be to revert to the older version of Windows. To ensure that this process was completed correctly, click on this, and you should be brought to an error. If it shows Windows could not find the old files, you've successfully saved your old Windows version!
It appears that this rollback setup only tries to detect the Windows.old file, or a specific structure within it. Simply by moving, Windows no longer sees the "C:\Windows.old" folder, and then throws an error (by assumption, this is what happpens).
By no means is this probably 100% safe, I've simply came across it. All upgrades from most version of Windows (XP to 7) or even "resetting" (saving files but reinstalling the OS) will create this Windows.old folder. On the other hand, there's still the question of exactly how to use this after you've moved it, after a month's period. I hope this has helped you if you've been presented with this!
Try this at your own risk.