Backup
First of all, you will want to Backup any settings or documents you want to keep from using this OS on any amount of time. Its always a good idea to Backup your files onto any device or cloud service, Some I would suggest are: Google Drive, Dropbox or Microsoft's own OneDrive
Downgrade Method 1:
- For Windows 7: Before you update, you might be able to create recovery media from a recovery partition on your PC using software provided by your PC manufacturer. Check the support section of your PC manufacturer's website for more info.
- For Windows 8.1 or Windows 8: You might be able to create a USB recovery drive. For more info, see Create a USB recovery drive. If you didn’t create a USB recovery drive before you installed the preview, you can create installation media for Windows 8.1. Source
Method 2: Found on PCA
Downgrade using the Windows 10 update and security settings
when you install windows 10, your pc makes a backup on your computer that does take up space but, you will also be able to go back to a previous version of windows. File is called Windows.old
To do this first open the Windows Start menu by clicking on the icon in the bottom left of the screen. Select Settings from the menu.
To do this first open the Windows Start menu by clicking on the icon in the bottom left of the screen. Select Settings from the menu.
Now you’ll see on option for Update & Security. Click that.
On the next page you’ll find a list of options on the left, one of which is Recovery. Click this and the main pane will display a variety of choices. The one you want is ‘Go back to a previous version of Windows’. Click 'Get started' to begin. If you’re using a laptop you’ll also need to connect it to a power source or the option won’t work.
You’ll now be presented with a blue screen (no death involved) asking you why you’re downgrading? Take a moment to fill this in, as it’s a helpful tool for Microsoft in gauging the user’s experience with Windows 10. Click Next when you’re done.
Before Windows starts the process it gives a couple more opportunities to cancel, and also reminds you that if you had a password on your previous version of Windows then you’ll require it once the process is finished. If you’re happy to proceed then just click Next, then put the kettle on.
Windows will now roll back your system to how it was before the technical preview was installed.
All info and pictures are from Pc Advisor I do not take credit for writing any of this, simply spreading information!