Windows boot error "INACCESSIBLE_BOOT_DEVICE" or "Boot failure" in an Azure VM

Applies to: Virtual Machine running Windows

Symptom


Windows doesn't start and generates 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.

How to fix


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:

Step 1: Verify if the Windows partition is marked as active

  1. Delete the virtual machine (VM). Make sure that you select the Keep the disks option when you do this.
  2. 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.
  3. 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
  4. 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. 

    boot folder
  5.  Run the following command as an administrator, which will create a boot record.
    bcdboot <Windows partition>:\Windows /S <windows partition>:
  6. Use DISKPART to check if the Windows partition is active:

    I. Run the following command to open diskpart:

    diskpart


     II.  List the disks on the system, and then select the OS disk you attached:

    list disk sel disk <number of the disk>

    III. List the volume, and then select the volume that contains Windows folder.

    list volsel vol <number of the volume>


    IV.  List the partition on the disk, and then select the partition contains Windows folder.

    list partitionsel partition <number of the Windows partition>

    V.  View the  status  of the partition:

    detail partition 

    Diskpart output


    If the partition is active, go to the step 2.

    If the partition is not active, run the following command line to active it:

    active

    Then run detail partition again to check if the partition is active.

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

Step 2: Repair the Boot Configuration data

  1. Run the following command line as an administrator to verifies the file system integrity and fixes logical file system errors.
    chkdsk <Windows partition>: /f 
  2. 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.
    bcdedit /store <Boot partition>:\boot\bcd /enum

    command prompt window: boot loader
  3. 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.
     
    bcdedit /store <Boot partition>:\boot\bcd /set {bootmgr} device partition=<boot partition>:bcdedit /store <Boot partition>:\boot\bcd /set {bootmgr} integrityservices enablebcdedit /store <Boot partition>:\boot\bcd /set {<Identifier>} device partition=<Windows partition>:bcdedit /store <Boot partition>:\boot\bcd /set {<Identifier>} integrityservices enablebcdedit /store <Boot partition>:\boot\bcd /set {<identifier>} recoveryenabled Offbcdedit /store <Boot partition>:\boot\bcd /set {<identifier>} osdevice partition=<Windows partition>:bcdedit /store <Boot partition>:\boot\bcd /set {<identifier>} bootstatuspolicy IgnoreAllFailures
  4. Detach the repaired OS disk from the troubleshooting VM. Then, create a new VM from the OS disk.