Fixed: Inaccessible Boot Device Windows Server 2012 R2 ( 6 Ways)

How to troubleshoot Windows server 2012 R2 cannot boot? Here are 5 useful ways for you! Additionally, you can backup your system through useful backup and restore software!


By Maggie / Updated on August 22, 2023

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Case: Challenge! Win Server 2012 R2 BSOD [INACCESSIBLE BOOT DEVICE]


Can you fix this server without restoring it from a backup?

Rebooted a server after pending windows updates and was left with "INACCESSIBLE BOOT DEVICE"


What does inaccessible boot device BSOD mean?

The Inaccessible Boot Device is a prevalent error or stop code that surfaces as a reference during a Blue Screen issue on Windows Server 2012 R2, as well as Windows Server 2008, 2016, and 2019. Typically, this error signifies that the Windows Server 2012 R2 OS encounters difficulty in accessing the system partition when initiating. Consequently, the system takes preemptive measures by shutting down and displaying a Blue Screen or Stop Error. This is done to safeguard against potential data corruption or loss.

Inaccessible Boot Error Message

Possible causes for server 2012 r2 inaccessible boot device

Numerous factors can contribute to the inaccessiblebootdeviceWindowsServer2012R2. This error commonly emerges during the boot sequence and signifies that the operating system cannot reach the storage device containing essential boot files.

Here are several potential reasons for boot issues on Windows Server 2012 R2 inaccessible boot device, also apply to inaccessible boot device Windows Server 2016 issue:

★Files in the boot partition are corrupted.
★Corruption of system files.
★Bad sectors on the main hard drive.
★Changes in the storage controller mode or BIOS settings.
★Faulty motherboard, storage controller, or hardware.
★Conflict between newly-installed hardware and other devices.
★Incorrectly written or conflicting newly-installed software.
★Corrupted Master Boot Record or missing Boot Configuration Data.

These factors can contribute to boot problems and should be considered when troubleshooting boot-related issues on your Windows Server 2012 R2 system.

5 Solutions to inaccessible boot device error

Option 1. Check hardware connections

This is the most straightforward and simple way to fix the inaccessible boot device issue. the thing you need to do is physically ensure that all hardware components, including hard drives and cables, are properly connected and functioning.

Option 2. Roll back recent Server update

Step 1. Press the power button to boot your Server. When the White circles start displaying, press the power button to power off the Server, and repeat 3 times until you can enter the recovery environment.

▶Warmly note:
If you cannot boot your server computer into recovery mode, please refer to this article How to Enter Windows Server 2016 Recovery Mode (3 Ways), which is also applicable to Server 2012 R2 system.

Step 2. Now you have entered the Recovery Mode, click Troubleshoot from the given recovery mode options.


Step 4. Choose Command Prompt in the Advanced options screen.

Step 5. Click the Admin account to load Command Prompt, and input the corresponding password for the administrator account. Then click Continue to enter the Command Prompt window.

Command Prompt

Step 6. In the elevated Command Prompt window, input the following commands in turn and hit Enter after each execution.

 reg load HKLM\temp c:\windows\system32\config\software: to load Windows registry to HKLM/temp.

reg delete "HKLM\temp\Microsoft\Windows\CurrentVersion\Component Based Servicing\SessionsPending" /v ● Exclusive: to delete the SessionsPending registry key. When you are prompted to confirm, type “Y” and press Enter.

reg unload HKLM\temp: unload the Windows registry

 MKDIR c:\temp\BadUpdates: to create a temp folder to hold the unnecessary Windows Server updates.

dism /image:C:\ /get-packages: list all installed updates.

Step 7. Now we need to execute other commands to delete the Install Pending Packages which might lead to the inaccessiblebootdeviceWindowsServer2012R2 error.

▶Note: Please pay attention to the result for Install Pending packages status and their Package Identity.

dism /image:c:\ /remove-package /packagename:Package-Identity /scratchdir:c:\temp\BadUpdates: replace the Package-Identity with the package name in your situation.

Now you can check if the problem is solved. If not, proceed to the next method.

▶Note: You can also use this method to troubleshoot the inaccessible boot device Windows Server 2016 issue.

Option 3. Boot Server back to last known good configuration

The Last Known Good Configuration, often abbreviated as LKGC, stands as a recovery feature thoughtfully integrated into all Windows versions by Microsoft. This tool serves as a lifeline when your Windows PC or Server encounters turmoil during its startup, triggered by a botched update, driver installation, or software arrangement. It operates as a beacon of restoration, allowing you to revert to the last functional state. Here's a simple guide to activate it:

Step 1. Access Advanced Options menu as #Option 2. And then click on Startup Settings.

Step 2. Once the Startup Settings screen emerges, initiate a Restart.


Step 3. As your system reboots, you'll encounter the Advanced Boot Options screen. Locate at Last Known Good Configuration (advanced) and press the Enter key to initiate the restoration process.

Last Known Good Configuration

Option 4. Check the boot partition for errors via Command Prompt

If the issue of Windows Server 2012 R2 inaccessible boot device VMware still persists, a potential resolution involves scrutinizing the boot partition for potential bad sectors using the Command Prompt. Follow these steps to execute this process:

Step 1. Launch Command Prompt in Recovery mode.

Step 2. Within the Command Prompt, input the following command: chkdsk c: /f, and then hit Enter to execute.


Option 4. Check the system file integrity

In addition to inspecting the system partition for potential errors, an alternative avenue is to leverage the SFC (System File Checker) tool. This utility is designed to conduct a comprehensive scan of your Windows system files, pinpointing and rectifying any instances of corruption. It operates by scrutinizing all safeguarded system files and seamlessly substituting compromised files with cached copies. To execute this procedure, simply follow these steps:

Open the Command Prompt window. Within the Command Prompt, input the following command sfc /scannow, and hit enter key to continue.

SFC Scannow

Option 5. Repair damaged MBR/BCD

Both MBR (Master Boot Record) and BCD (Boot Configuration Data) play pivotal roles in ensuring the successful booting of a Server. Consequently, if your Server 2012 R2 encounters a disruption in its typical boot process, it's prudent to explore avenues for repair. Then you can repair MBR/BCD via Command Prompt.

Step 1. Gain access to the Command Prompt window within the Recovery mode.

Step 2. Enter the following commands, pressing Enter after each one:

bootrec /fixmbr
bootrec /rebuildbcd

Recommended: always backup your system to prevent data loss danger

In fact, you cannot guarantee to fix everything at all times. Additionally, backing up your important data in advance will definitely add one more protection layer on your computer. Opting for professional and dependable third-party backup software like AOMEI Backupper Server is a wise decision. This software streamlines the system backup process, requiring just a few simple steps that save you valuable time.

✦It offers a Schedule Backup feature, allowing you to establish regular backup routines such as Daily, Weekly, or Monthly backups.
✦You can backup almost everything on your PC, including files and folders, disks and partitions, and systems as well. You can easily create image backup in Windows Server beforehand, then you will have no worry to lose your operating system in the future.
✦Along with incremental and differential backup, you can save a lot of storage space.

Now, download AOMEI Backupper Server, install and launch it. Then, follow the steps below to back up system.

Download Free Trial Windows Server & PC
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Step 1. On the left tab page, select Backup and then select System Backup.

System Backup

Step 2. And you can see the system and boot-related partition are listed automatically,

Step 3. Then you just need to select a destination path to save image files.

▶Note: you can backup your system on various places, including local path, Share and NAS device and so on.

Select Path

Step 4. You can create a scheduled system image backup by clicking Schedule Backup. Here you can create schedules.

Schdule Backup

Step 5. Click Start Backup button and wait for the process to complete.


You can try the above methods to fix the error “inaccessible boot device Windows Server 2012 R2”. But it will cost you a lot of time. And there is no guarantee that the error will be successfully repaired every time. Therefore, you need to consider make an advanced preparation for your system. AOMEI Backupper is a good choice.

Maggie · Editor
Maggie is a technical editor from AOMEI and troubleshoots technical problems against data protection. She has received professional and systematic technical training. With a focus on user experience, security, and problem-solving, she always puts herself in the readers' shoes and provides them with valuable technical insights.