Users of Windows 10/8 may have noticed that it includes a new recovery feature called Startup Repair. If your Windows 10/8 is not able to boot or start-up, Automatic Repair, earlier called Startup Repair will come into action and try to diagnose and fix the issue. It will scan system files, registry settings, configuration settings and more and try to fix the problem on its own, automatically.
When the computer boots up, and the OS detects that there is something wrong with the files. It will trigger Automatic Startup Repair. If it doesn’t, then try interrupting the boot process three times in a row – for when you do this, Automatic Repair mode will appear.
Automatic Startup Repair in Windows
If you want to access and run Automatic Repair manually, you need to boot into Advanced Startup options. This will let you start Windows from an external device, change Windows startup settings or restore Windows from a Factory image. On a restart, you will see the following screen. 
From the WinRE screen, select Troubleshoot > Advanced Options. 
Under Advanced options, select Automatic/Startup Repair. 
You will be asked to select the User Account to continue. Do so and continue. If asked, enter your password too and click on Continue. Windows Automatic Repair will now commence and try to identify and resolve the problem. This process may take some time, and your system may even boot.
Once the process completes successfully, you will see a message to this effect.
Automatic Startup Repair couldn’t repair your PC
If Starup Repair fails, and you get an error message Automatic Startup Repair couldn’t repair your PC, you may check the log file at:
C:\Windows\System32\Logfiles\Srt\SrtTrail.txt
You may also want to check this post on Windows fails to boot; Automatic Repair, Refresh, Reset PC also fail.
