Fixed: What to Do When Windows Fails to Start?

April 30, 2019

This post explains what to do when the Windows fails to start, so it is quite a worthwhile to take a few minutes to browse the content. Then you can easily fix “Windows failed to start” issue.

Scope of “Windows fails to start”

Some computer users may face the problem that Windows fails to start when they power up the machine, and get a prompting message on their screen as shown below.

Windows Fails To Start

According to the messages, we can get the conclusion that if windows files get damaged or lost, the Windows will fail to start. After realizing what leads to this error, next let’s figure out what to do when Windows fails to start.

Solutions to fix “Windows fails to start”

In order to fix the problem, we searched the Internet and gathered 3 different solutions for your convenience.

1. Launch Startup Repair

As shown in the screenshot above, the computer provides you with two options: Launch Startup Repair (recommended) and Start Windows Normally.

Now that you are reading this post, I think you must have tried the option “Start Windows Normally” but got no success apart from boot loop. So it’s time to try the first option (Startup Repair) to check whether the windows files are damaged/lost or not, and fix the problem.

Choose “Launch Startup Repair (recommended)” use the arrow key, and follow the hints to finish the repair. If any problem is found, the Startup Repair will fix them automatically. The checking and repairing process will cost minutes.

Startup Repair

2. Using CMD

If the first solution gives no useful output or you stuck in Startup Repair loop, you can enter the Safe Mode to fix “Windows fails to boot ” by following the guides.

(1) Restart your computer, press F8 before the Windows logo appears. Select “Safe Mode” using the arrows key to enter “Safe Mode” interface.

(2) Press win+r simultaneously to run the windows, input “cmd” and click“OK”.

(3) Then in the DOS program, input and run the following three commands directly:

bcdedit /set {default} osdevice boot

bcdedit /set {default} device boot

bcdedit /set {default} detecthal 1


(4) Close the Safe Mode and restart the computer.

3. AOMEI Partition Assistant

If the problem “windows fails to start” still remains unsolved after trying the first two solutions, you need to turn to a third-party tool- AOMEI Partition Assistant. It is a professional disk partition manage tool, which enables you to create a bootable CD or USB flash drive based on Windows PE in a few clicks. The WinPE bootable media could check and fix the damaged disk, and then you can get rid of the situation of Windows startup failure easily.

Next content is about how to make a WinPE bootable media with the help of AOMEI Partition Assistant?

Before you do

  • Insert a blank CD/DVD or plug an empty USB drive to a working Windows computer. If you don’t have USB or CD/DVD, AOMEI Partition Assistant is also able to help create a bootable ISO file, which can be burned to CD/DVD. But a burner (a kind of software which can make bootable CD/DVD) is necessary in this situation.

  • If your computer runs on Windows XP, Windows 2003, Windows Vista, and Windows 2008, then you will have to download Windows AIK (Automated Installation Kit) to configure and deploy operating system to new hardware. On Windows 7/8/8.1/2012 and Server 2008 R2, you can directly make a Windows PE bootable media without downloading and installing Windows AIK.

Steps of creating a bootable WinPE media with AOMEI Partition Assistant

(1) Download the freeware on a working-well computer.

(2) Install and run the software, click the “Make Bootable CD Wizard” in the left panel under Wizard column, confirm your operation and click “Next”.

Make Bootable Media

(3) Three ways are offered to create bootable media based on Windows PE. Choose one according to your requirements. Here we will choose USB as an example. Click “Proceed” to finish the rest operation.

Choose USB Drive

Note: The USB will be formatted and all data on it will be deleted, so please make a backup via AOMEI Backupper.

(4) The process will take a few minutes.


Part 1. Check system partition error

Plug the bootable USB drive (it contains a pre-installed AOMEI Partition Assistant) into your computer which fails to boot. Restart it from the USB drive and once login in, you will see the AOMEI Partition Assistant is running. Then click the system drive and click "Advanced">“Check Partition" to check and fix the partition error.

Check Partition And Fix Errors

Part 2. Rebuild MBR

If there is no error found on the system drive, you can rebuild MBR on the system disk to check if the Windows boot failure can be fixed. 

Step 1. In the main interface of AOMEI Partition Assistant Standard, right click the system disk and select "Rebuild MBR".

Rebuild System Disk MBR

Step 2. Choose a proper MBR type for your current OS and click "OK".

Choose MBR Type

Step 3. Click Apply and then Proceed to start rebuilding MBR.


Bottom Line

Now you know what to do when Windows fails to start in Windows7/8/10. After a brief comparison, it is easy to find the AOMEI Partition Assistant provides the best and most effectively way. Besides, you can also use it to solve many other disk problems like fixing RAW drive, repairing damaged SSD, and solving USB flash drive 0 bytes or no media. You can even optimize SSD performance by making 4K alignment, erasing SSD drives completely after you upgrade to AOMEI Partition Assistant Professional.