In the guide to installing the preview build, the first step which I mentioned was to backup your data. Well now it's the time to restore that backed up data. But unlike installing the update, restoring back to Windows Phone 8.1 from the Windows 10 preview requires the help of a computer and also an internet connection. The entire process will take about an hour to complete and your device must have at least a 40% charge.
Another thing to note is that if you were previously on the latest Preview for Developers build, you'll be restored back to the latest firmware for your device. So, essentially you'll be back to square one in terms of software and you will need to reinstall the Preview for developers build(s) again.
Step 1: Download and install the Windows Phone Recovery ToolTo restore your device back to Windows Phone 8.1, you'll need to download the windows phone restore app from Microsoft. After downloading, follow the wizard to install the application. The installation process is quite quick and will not take much time.
Step 2: Connect your device to the computerAfter that launch the windows phone restore app and also connect your device to the computer via a microUSB cable. Your device should be detected automatically, if not reboot your PC and try again (this should work). Follow the steps on the program to download the firmware for your device (approx 1.7GB in size). After that is done, you should be able to unplug your device as the software is being installed onto your device.
|If you were beamed up this error, just click exit and retry the download|