Windows boot error INACCESSIBLE_BOOT_DEVICE in an Azure VM

Article
03/27/2024

This article provides a solution to an issue where a Windows virtual machine (VM) doesn't start with the error "INACCESSIBLE_BOOT_DEVICE" or "Boot failure".

Original product version: Virtual Machine running Windows
Original KB number: 4010143

Symptoms

A Windows VM doesn't start and generates one of the following errors:

Boot failure. Reboot and Select proper Boot device or Insert Boot Media in selected Boot device.

Your PC ran into a problem and needs to restart. We'll restart for you. If you'd like to know more, you can search online later for this error: INACCESSIBLE_BOOT_DEVICE

Cause

This issue occurs for one of the following reasons:

The Boot Configuration Data (BCD) is corrupted.
The partition that contains the Windows installation is inactive.

Stop (de-allocate) and start the VM

Tip

If you have a recent backup of the VM, you may try restoring the VM from the backup to fix the boot problem.

To fix the issue, stop (de-allocate) and start the VM then recheck to see if issue persists. If the issue persists, follow these steps:

Verify if the Windows partition is marked as active

Note

This section applies only to Generation 1 VMs because Generation 2 VMs that use UEFI don't use an active partition.

Delete the VM. Make sure that you select the Keep the disks option when you do this.
Attach the OS disk as a data disk to another VM (a troubleshooting VM). For more information, see How to attach a data disk to a Windows VM in the Azure portal.
Connect to the troubleshooting VM. Open Computer management > Disk management. Make sure that the OS disk is online and that its partitions have drive letters assigned.
Identify the Boot partition and the Windows partition. If there's only one partition on the OS disk, this partition is the Boot partition and the Windows partition.

If the OS disk contains more than one partition, you can identify them by viewing the folders in the partitions:

The Windows partition contains a folder named "Windows," and this partition is larger than the others.

The Boot partition contains a folder named "Boot." This folder is hidden by default. To see the folder, you must display the hidden files and folders and disable the Hide protected operating system files (Recommended) option. The boot partition is typically 300 MB~500 MB.
Run the following command as an administrator, which will create a boot record.
```
bcdboot <Windows partition>:\Windows /S <windows partition>:
```
Use DISKPART to check if the Windows partition is active:
1. Run the following command to open diskpart:
```
diskpart
```
2. List the disks on the system, and then select the OS disk you attached:
```
list disk  
sel disk <number of the disk>
```
3. List the volume, and then select the volume that contains the Windows folder.
```
list vol
sel vol <number of the volume>
```
4. List the partition on the disk, and then select the partition contains the Windows folder.
```
list partition
sel partition <number of the Windows partition>
```
5. View the status of the partition:
```
detail partition
```
  If the partition is active, go to the step 2.
  
  If the partition isn't active, run the following command line to active it:
```
active
```
  Then run detail partition again to check if the partition is active.
Detach the repaired disk from the troubleshooting VM. Then, create a VM from the OS disk.

Repair the Boot Configuration Data

Run the following command line as an administrator to verifies the file system integrity and fixes logical file system errors.
```
chkdsk <Windows partition>: /f
```
Run the following command line as an administrator, and then record the identifier of Windows Boot Loader (not Windows Boot Manager). The identifier is a 32-character code and it looks like this: xxxxxxxx-xxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. You will use this identifier in the next step.
1. For Generation 1 VMs:
```
bcdedit /store <Boot partition>:\boot\bcd /enum /v
```
2. For Generation 2 VMs:
```
bcdedit /store <Volume Letter of EFI System Partition>:EFI\Microsoft\boot\bcd /enum /v
```

Repair the Boot Configuration Data by running the following command lines. You must replace these placeholders by the actual values:

Note

This step is applied to most Boot Configuration Data corruption issues. You need perform this step even if you see the Device and OSDevice are pointing to the correct partition.

<Windows partition is the partition that contains a folder named "Windows."
<Boot partition> is the partition that contains a hidden system folder named "Boot."
<Identifier> is the identifier of Windows Boot Loader you found in the previous step.

For Generation 1 VMs:

bcdedit /store <Boot partition>:\boot\bcd /set {bootmgr} device partition=<boot partition>:
bcdedit /store <Boot partition>:\boot\bcd /set {bootmgr} integrityservices enable
bcdedit /store <Boot partition>:\boot\bcd /set {<Identifier>} device partition=<Windows partition>:
bcdedit /store <Boot partition>:\boot\bcd /set {<Identifier>} integrityservices enable
bcdedit /store <Boot partition>:\boot\bcd /set {<identifier>} recoveryenabled Off
bcdedit /store <Boot partition>:\boot\bcd /set {<identifier>} osdevice partition=<Windows partition>:
bcdedit /store <Boot partition>:\boot\bcd /set {<identifier>} bootstatuspolicy IgnoreAllFailures

If the VHD has a single partition and both the BCD folder and Windows folder are in the same volume, and if the previous setup didn't work, then try replacing the partition values with boot, as shown below:

bcdedit /store <BCD FOLDER - DRIVE LETTER>:\boot\bcd /set {bootmgr} device boot
bcdedit /store <BCD FOLDER - DRIVE LETTER>:\boot\bcd /set {bootmgr} integrityservices enable
bcdedit /store <BCD FOLDER - DRIVE LETTER>:\boot\bcd /set {<IDENTIFIER>} device boot
bcdedit /store <BCD FOLDER - DRIVE LETTER>:\boot\bcd /set {<IDENTIFIER>} integrityservices enable
bcdedit /store <BCD FOLDER - DRIVE LETTER>:\boot\bcd /set {<IDENTIFIER>} recoveryenabled Off
bcdedit /store <BCD FOLDER - DRIVE LETTER>:\boot\bcd /set {<IDENTIFIER>} osdevice boot
bcdedit /store <BCD FOLDER - DRIVE LETTER>:\boot\bcd /set {<IDENTIFIER>} bootstatuspolicy IgnoreAllFailures

For Generation 2 VMs:

bcdedit /store <Volume Letter of EFI System Partition>:EFI\Microsoft\boot\bcd /set {bootmgr} device partition=<Volume Letter of EFI System Partition>:
bcdedit /store <Volume Letter of EFI System Partition>:EFI\Microsoft\boot\bcd /set {bootmgr} integrityservices enable
bcdedit /store <Volume Letter of EFI System Partition>:EFI\Microsoft\boot\bcd /set {<IDENTIFIER>} device partition=<WINDOWS FOLDER - DRIVE LETTER>:
bcdedit /store <Volume Letter of EFI System Partition>:EFI\Microsoft\boot\bcd /set {<IDENTIFIER>} integrityservices enable
bcdedit /store <Volume Letter of EFI System Partition>:EFI\Microsoft\boot\bcd /set {<IDENTIFIER>} recoveryenabled Off
bcdedit /store <Volume Letter of EFI System Partition>:EFI\Microsoft\boot\bcd /set {<IDENTIFIER>} osdevice partition=<WINDOWS FOLDER - DRIVE LETTER>:
bcdedit /store <Volume Letter of EFI System Partition>:EFI\Microsoft\boot\bcd /set {<IDENTIFIER>} bootstatuspolicy IgnoreAllFailures

Detach the repaired OS disk from the troubleshooting VM. Then, create a new VM from the OS disk.

Contact us for help

If you have questions or need help, create a support request, or ask Azure community support. You can also submit product feedback to Azure feedback community.