This is been routine practice in my camp for eons. Currently using RegBak + Tweaking.com's very excellent RegistryBackup program, BOTH simple standalones/portable. There is been circumstances on numerous occasions where things looked totally bleak such as unable to boot back into the GUI and other issues. As another alternative enter Linux Mint on a stick. Or any PE on a USB Pen that can open disk for writing where it is as simple as copying over saved Registry Files MANUALLY and the Windows system was right back on track again like nothing happened. That Automatic Repair from Microsoft is a pure joke when they very well could have made some alternate provision for something as simple as restoring a previous registry backup that they could done themselves a long time ago. But no matter, many Windows issues which I personally encountered didn't necessitate to do an image restore when just a simple Registry Restore returned the system back to normal operation.