Boot selection failed because required device is inaccessible, 0xc0000225

This article provides solutions to fix the “0xc0000225, Boot selection failed because a required device is inaccessible” error. You may see this error in any of the following scenarios:

While upgrading your Windows operating system.
While performing a clean installation of Windows OS.
While installing Windows Updates.
While turning on an Azure VM.

There could be multiple causes of this error. Here, we will also talk about some causes of this error.

Fix 0xc0000225, Boot selection failed because a required device is inaccessible

Use the following solutions to fix the “0xc0000225, Boot selection failed because a required device is inaccessible” error on your Windows computer.

Change the boot order
Run a Startup Repair
Repair Master Boot Record
Repair corrupted disks and system files
Perform a System Restore and uninstall your antivirus
Add the OSDEVICE Variable (solution for Azure VM users)

Let’s see all these fixes in detail.

1] Change the boot order

It is clear from the error message that the computer is not able to access the hard drive that contains the Windows operating system. Such types of problems occur when you have more than one hard drive installed on your system and your system is not booting from the correct hard drive (the hard drive that contains the Windows operating system).

If your system is showing you this error message on restart, there are maximum chances that your computer is not able to access the correct hard drive. In this case, you should check the boot order. For this, you have to enter your system BIOS. Computers of different brands have different methods or keys to enter into BIOS.

After entering BOS, check the boot order. The hard drive shown in the first position is used to boot Windows. If you see that your boot drive is not in the first place, change the boot order and bring the boot drive in the first place. After doing that, save the changes and restart your computer. This will fix the problem.

If the boot order is correct the SATA cable might have been damaged. A SATA cable is used to connect the hard drive to the computer. If the cable is damaged or your hard drive is not connected properly with the SATA cable, you will experience boot errors.

2] Run a Startup Repair

Startup Repair is used to repair corrupted files and Windows boot problems. Your computer is showing you the error message on boot. Hence, running the Startup repair may help. To run Startup Repair, you have to enter Windows Recovery Environment. To do so, press and hold the Shift key and then restart your computer. This will take you to Windows Recovery Environment.

If this does not work, you can enter Windows RE by interrupting the normal boot process. The following steps will guide you on this:

Force shut down your computer by pressing and holding the power button.
Wait for a few seconds and turn on your computer. When you see the Windows logo or your computer manufacturer’s logo, immediately press and hold the power button to force shut down your computer.
Repeat the above steps three to four times. After that, Windows will automatically boot into Windows Recovery Environment.

After entering Windows Recovery Environment, go to “Troubleshoot > Advanced Options > Automatic Repair.” Let Windows repair your PC. After the completion of Automatic Repair, check if you can start your computer.

You can also use Installation Media to repair your computer.

3] Repair Master Boot Record

One possible cause of the boot errors is Master Boot Record corruption. If the above method did not work, the problem might be associated with Master Boot Record. You should repair Master Boot Record (MBR) and see if it helps.

4] Repair corrupted disks and system files

Hard Disk and system file corruption can also lead to boot errors. If your disk has bad sectors, your computer may not boot properly or you experience some other errors. Repair corrupted disks and system files. Because you cannot enter your system due to the error “0xc0000225, Boot selection failed because a required device is inaccessible,” you have to enter Windows Recovery Environment and then launch the Command Prompt.

We have already talked about the ways to enter Windows Recovery Environment above in this article. After entering Windows RE, go to “Troubleshoot > Advanced Options > Command Prompt.” In the Command Prompt, run the CHKDSK scan and SFC scan to repair your hard disk and system image files.

5] Perform a System Restore and uninstall your antivirus

As stated earlier in this article, the error can also occur while installing Windows Updates. In Windows 11/10, you can download and install updates via the Settings app. In order to apply the installed update on your system, Windows requires you to restart your computer. Some affected users reported that the error appears when they restart their computers after installing Windows Update. According to them, it was their third-party antivirus interrupting Windows Update and preventing their systems from applying the Windows Update.

If such a thing happens to you, you can restore your system to the previous working state by using the System Restore tool. System Restore tool is designed by Microsoft that helps you protect and repair your computer software. If it is turned on, it takes a snapshot of your registry and system files and stores them as a restore point. When you make any change to your system, like installing a new program, a new restore point is created automatically. If a problem occurs, you can use these restore points to restore your system to the previous working state.

Restore your system and uninstall your antivirus. After that, you will be able to install the Windows update. To run the System Restore tool, you have to boot your computer in Windows Recovery Environment. We have already shared the steps to boot into Windows RE. After booting into Windows Recovery Environment, go to “Troubleshoot > Advanced Options > System Restore.” You will see the restore points with the date they were created on. Select the restore point which was created before the problem started occurring.

After restoring your computer, you should be able to boot it successfully without this error message. Now, uninstall your antivirus and then install Windows Update.

6] Add the OSDEVICE Variable (solution for Azure VM users)

If this error occurs on Azure VM, you have to add the OSDEVICE variable. For this, you will need the identifier on the active partition. Make sure that you have attached the OS disk as the data disk to the troubleshooting VM.

The OS Disk should be online and a drive letter should be assigned to it. If not, assign a drive letter to the OS drive. You can use the Diskpart utility to assign a drive letter to the OS drive. The steps for the same are written below:

Open an elevated Command Prompt.
Type diskpart.
Type list disk. You will see all the disk drives installed in and connected to your computer.
Now, select the OS disk. To do so, type select disk #. # is the disk number.
Type list partition.
Type select partition #. # is the partition number.
Type assign letter=x. You can assign any letter to the targeted partition.

Close Diskpart and launch the administrator Command Prompt. If you have installed Generation 1 VM, run the following command in the administrator Command Prompt.

bcdedit /store <LETTER OF BOOT FOLDER>:\boot\bcd /enum

For Generation 2 VMs, execute the following command in the administrator Command Prompt.

bcdedit /store <LETTER OF EFI SYSTEM PARTITION>:EFI\Microsoft\boot\bcd /enum

Note down the identifier. You will need it to add the OSDEVICE.

For Generation 1 VMs, execute the following command in the administrator Command prompt to add OSDEVICE.

bcdedit /store <LETTER OF BOOT FOLDER>:\boot\bcd /set {<IDENTIFIER>} OSDEVICE BOOT

For Generation 2 VMs, execute the following command in Command Prompt Admin.

bcdedit /store <LETTER OF EFI FOLDER>:EFI\Microsoft\boot\bcd /set {<IDENTIFIER>} OSDEVICE BOOT

If you have multiple partition OS disks, then

Type the following command in the admin Command Prompt for Generation 1 VMs.

bcdedit /store <LETTER OF BOOT FOLDER>:\boot\bcd /set {<IDENTIFIER>} OSDEVICE partition=<LETTER OF WINDOWS FOLDER>:

Type the following command in the admin Command Prompt for Generation 2 VMs.

bcdedit /store <LETTER OF EFI FOLDER>:EFI\Microsoft\boot\bcd /set {< IDENTIFIER>} OSDEVICE partition=<LETTER OF WINDOWS FOLDER>:

Now, run the following command to repair the Virtual Machine. But before doing this, you should enable the Serial Console and memory dump collection.

az vm repair run

You can visit microsoft.com for more information on fixing this error on Azure VM. If the problem is not solved, contact Microsoft Support.

Read: Fix INACCESSIBLE_BOOT_DEVICE Blue Screen error.

What causes inaccessible boot device?

If you see the inaccessible boot device error on your system, your computer is unable to access the hard drive on which the operating system is installed. To fix this error, change your boot order. If this does not work, your SATA cable might be faulty or you might have not connected your hard drive to your computer properly via the SATA cable.

We have covered some troubleshooting tips in this article that will help you.

How do I fix the inaccessible boot device with USB?

If you see the inaccessible boot device message while installing or upgrading Windows from USB, it means that your computer is not able to access the USB flash storage device. To fix this, change the boot order and place your USB flash storage device in the first place in the boot order in BIOS.

I hope the solutions explained in this article may help you resolve the issue.