By Yuka / Last update November 29, 2021

User Case

How can I fix Inaccessible Boot Device BSOD error?

“I'm trying to upgrade my SSD with Windows 10 and a few programs on it from a 120GB model to a new 1 TB NVMe M.2 SSD. I cloned the original drive to the new drive. After the cloning, I move the new drive to the mother board in the old one's place. However, when I try boot from the new drive by selecting it in the BIOS boot menu. I get a bluescreen error that INACCESSIBLE BOOT DEVICE after clone to NVMe M.2 SSD. After a few times it goes into Automatic Repair mode but this does not help. Is there a way to debug or fix this issue? Thanks!”

- Question from Super User

Windows 10 Inaccessible Boot Device After Clone

Inaccessible Boot Device is one of the typical BSOD (Blue Screen of Death) errors with the code 0x0000007b. Simply put, the message means that Windows lost access to the system partition during startup. When you encounter this error after cloning, you can’t boot Windows 10 normally from the cloned disk and access the computer data. But what are the causes of the inaccessible boot device error after clone? How to fix it? Read on to find out.

What Causes Inaccessible Boot Device Error in Windows 10 and How to Fix it

Here are five different reasons for this BSOD error. Solutions are also available.

Set the wrong drive to boot from

The wrong boot device may cause Windows 10 inaccessible boot device error. If you have more than one hard drive on your computer, it's a good idea to go into the BIOS and change the boot order to start from the cloned hard drive.

  1. Restart your computer. When the startup screen appears, continuously press a specific key (usually F2, F8, F12, Del) to enter BIOS Setup.
  2. Select Boot and choose the cloned hard drive as the first boot option.
  3. Press F10 to save and exit the BIOS. Then restart the PC to check if it can start successfully.

Change Boot Order BIOS

GPT/MBR conflict

MBR and GPT are two different partition styles. Both have different boot modes. MBR works with Legacy boot mode and GPT works with UEFI boot mode. If the partition style is not compatible with the boot mode, there will also be a problem that the cloned drive cannot boot normally in Windows 10.

To change the boot mode, you can take the following steps:

  1. Restart your computer. When the startup screen appears, continuously press a specific key (usually F2, F8, F12, Del) to enter BIOS Setup.
  2. Under "Boot" tab, select "UEFI/BIOS Boot Mode". Then choose "Legacy" or "UEFI" according to the partition style.
  3. Press F10 to save and exit the BIOS. Then restart the PC to check if it can start successfully.

Legacy or UEFI

Cloning a wrong disk

Cloning the wrong disk (data disk instead of operating system) can also cause the error of Windows 10 Inaccessible Boot Device. You can check if cloned disk contains OS. If not, re-clone the disk that contains OS to the hard drive.

Here are the steps to check:

  1. Install the cloned hard drive to your computer.
  2. Restart your computer from the original disk.
  3. Open Windows File Explorer and open the cloned drive.
  4. Look for the "Windows" folder on the cloned drive.
     If
    you find it, it means that you have an operating system installed on the drive, and the Inaccessible Boot Device error may be caused by another reason.
     If not, you probably have cloned a wrong disk. And you'll have to re-clone to the hard drive.

Source disk has bad sectors

Sometimes, if the source disk consists of bad sectors or is infected with a virus, the error of Windows 10 Inaccessible Boot Device after clone will happen easily. You can try to fix this BSOD error by running the CHKDSK utility.

★ Note: It's possible that running CHKDSK to repair the hard drive corruption would cause total data loss. So, backup files in advance.

To run the CHKDSK utility in Windows 10, take the following steps:

  1. Start your computer from the original disk.
  2. Type cmd in the search box and right-click to select Run as administrator.
  3. Next, type " chkdsk c: /f /r " and press “Enter”.

Command Prompt Chkdsk

  1. Then you will be asked if you would like the CHKDSK utility to perform the scan the next time the system restarts. Simply type y (for yes) and press Enter.
  2. Restart your computer, and the process may take a while to complete. When the process gets finished, re-clone Windows 10 to the hard drive.
  3. Then, reboot your system from the cloned hard drive. Check if you have fixed the Inaccessible Boot Device error.

System is corrupted during cloning process

If you think the system files are corrupted during cloning, then the Inaccessible Boot Device error occurs after cloning, you can run system file checker to check the disk and repair the damaged file.

  1. Do not operate until the computer restarts automatically. It will attempt to repair and pop-up following screen. Choose “Advanced options” then.

Automatic Repair

  1. Select Troubleshoot > Advanced options > Command Prompt.

Advanced Options

  1. Type sfc /sannow in the command prompt and press Enter to run it.

SFC

Most Secure Bootable Disk Cloning Software for Windows

If the error of Windows 10 Inaccessible Boot Device is not resolved after trying all of the above methods, I recommend that you use the most secure bootable disk cloning software—AOMEI Backupper Professional for Windows 10/8/7/XP/Vista, etc. It has multiple cloning features, including disk clone, system clone and partition clone. And with its help, you can securely boot from the cloned disk. It has some advantages as follows:

✪ You can use it to clone MBR to GPT, MBR to MBR, GPT to GPT, GPT to MBR without converting the partition styles.
✪ By its System Clone feature, this software automatically selects the System drive and related drives by default. If you want to migrate OS, don’t worry about cloning the wrong disk. It ensures securely boot after cloning. You can also use it to create bootable media in case of some startup problems.
✪ It supports 3 cloning mode, including Intelligent clone,
Sector by sector clone, live clone. Its default cloning method Intelligent clone will clone only used sectors from one hard drive to another while skipping bad sectors. Therefore, you can also clone large HDD to smaller SSD.
✪ It supports multiple HDD/SSD types. And SSDs are most used for its faster reading and writing speed than HDDs. It only takes a few clicks to
clone to M.2 SSDs, NVMe SSDs, etc.

You can follow the graphic tutorial below to learn how to use this software to perform Disk Clone to clone a disk contains the Windows 10 operating system and then securely boot Windows 10 from the cloned hard drive. First of all, download and install it.

Download Free Trial Win 10/8.1/8/7/XP
Secure Download

Preparations:
▶ Connect or install the target disk to your computer in advance and make sure it can be detected.
▶ The cloning process will delete all data on the destination disk, so backup files if needed.

Step 1. Launch AOMEI Backupper. In the dark blue interface, click Clone -> Disk Clone.

Disk Clone

Step 2. Then select the disk that contains OS and click Next.

Select Source Disk

Step 3. Select the destination disk and click Next.

Select Destination Disk

Step 4. Confirm the settings and click Start Clone.

Start Clone

Tips✍:
✫ SSD Alignment:
if the destination is an SSD, you can check this option to improve its reading and writing speed.

✫ Edit Partitions: You can change the partition size using this feature.

When the cloning process is complete, you can enter BIOS to boot from the cloned disk contains Windows 10 operating system securely.

Summary

After reading this article, I assume that you may have learned a lot about the error of Windows 10 Inaccessible Boot Device after clone. There are many reasons for this BSOD problem, and the solutions are relatively different. Mastering each solution is too cumbersome. Therefore, I strongly recommend that you use the most secure bootable disk cloning software—AOMEI Backupper Pro.

Its powerful functions can help you protect your data with ease. Whether you want to backup, clone, restore, or synchronize files, it can help you instantly. In addition to solve this BSOD error in Windows, it can also be a quick solution to Windows 10 Startup Repair Not Working problem, OneDrive Sync Pending error, etc. Try it right now.