Repair and cause of “Inaccessible Boot Device” that keeps restarting in Windows 10 and 11

This time, we will explain the causes and how to fix the error "Inaccessible Boot Device" on Windows 10 or Windows 11, which causes the system to restart repeatedly or become stuck in a loop.

An error called Inaccessible Boot Device can occur if you are unable to access the hard disk or other device used to boot the OS.

How to repair Inaccessible Boot Device

If you encounter an error called Inaccessible Boot Device on Windows 10 or Windows 11 and keep rebooting, you may be able to repair it using the methods below.

• Check if the HDD/SSD is recognized by BIOS (UEFI)
• Uninstall updates
• Repair with recovery drive
• Update BIOS (UEFI) to the latest version
• Run CHKDSK or SFC /SCANNOW at the command prompt
• Try a system restore
• Try startup repair
• Change SATA controller mode to AHCI in BIOS (UEFI)
• Try rebuilding the MBR (Master Boot Record)
• Repair boot sector with TestDisk
• Replace HDD or SSD
• Recovery or clean install
• replace motherboard

Check if the HDD/SSD is recognized by BIOS (UEFI)

If an Inaccessible Boot Device error occurs, checking whether the HDD or SSD is recognized by the BIOS (UEFI) may help resolve the issue.

To start the BIOS (UEFI), you need to press the startup key ("F2" for manufacturer's PCs, "Delete" for homemade PCs) on the manufacturer's logo screen that appears when you start your computer. The activation key varies depending on the manufacturer.

If it is not recognized, please check whether the HDD or SSD is properly connected to your computer.

Uninstall updates

It is possible that the error is caused by a recently updated program.
In such cases, uninstalling the update program may eliminate the error.

If an error occurs, you need to start the recovery environment from the installation media and uninstall it.

[How to uninstall updates]

1. Boot from the installation media.
2. Configure language etc.
3. Select "Repair your computer."
4. Select "Troubleshoot".
5. Select Advanced Options.
6. Select "Command Prompt".
7. Enter "Dism /Image:○:\ /Get-Packages (○ is the drive letter containing the OS)".
8. Find the recent update ID from the listed time.
9. Type "Dism.exe /image:c:\ /remove-package /○ (○ is the ID of the recently installed update)" and press the Enter key.
10. Restart your computer.

Repair with recovery drive

If you receive an Inaccessible Boot Device error, you may be able to fix it using a recovery drive.

→Try startup repair

Update BIOS (UEFI) to the latest version

If Inaccessible Boot Device occurs, updating the BIOS (UEFI) may resolve the error.

The steps vary depending on the manufacturer, so please check.

Run CHKDSK or SFC /SCANNOW at the command prompt

If an Inaccessible Boot Device occurs, running CHKDSK or SFC/SCANNOW at a command prompt may resolve the issue.

[How to check hard disk errors using command prompt]

1. Force shut down the PC repeatedly or use the installation media to boot into the Windows recovery environment.
2. Select Advanced Options.
3. Select "Troubleshoot".
4. Select Advanced Options.
5. Select "Command Prompt".
6. Select an administrator account.
7. Enter your password.
8. A command prompt will start.
9. Enter the chkdsk command.

[Try repair with sfc /scannow command]

1. Start Command Prompt or PowerShell as administrator.
2. Type sfc /scannow and press Enter.
3. A scan will be performed, and if any inconsistencies are found, repairs will be performed automatically.

Try a system restore

If you are experiencing an Inaccessible Boot Device error, trying a system restore may fix the problem.

[How to restore the system]

1. Enter the recovery environment using a recovery drive or similar.
2. Select "Troubleshoot".
3. Select "System Restore".
4. Select the appropriate OS.
5. Select Next.
6. Select a restore point.
7. Select Next.
8. Select Done.
9. Select "Yes".
10. Once complete, select Restart.

Try startup repair

Booting from a recovery drive or installation media and performing a Startup Repair may resolve Inaccessible Boot Device errors.

Startup Repair can be performed automatically after consecutive Windows startup failures, or it can be run manually.

Please refer to the article below for instructions on how to create a recovery drive (system repair disk).

[Easy] How to create and use a system repair disk on a USB memory

[How to perform startup repair]

1. Boot your PC from the recovery drive.
2. Select "Troubleshoot".
3. Select Advanced Options.
4. Select "Startup Repair".
5. Select your account.
6. Enter your password.

Change SATA controller mode to AHCI in BIOS (UEFI)

If you receive an Inaccessible Boot Device error, changing the SATA controller mode to AHCI in the BIOS (UEFI) may resolve the issue.

[How to change the SATA controller mode to AHCI in BIOS (UEFI)]

1. Boot into BIOS (UEFI).
2. Select "Advanced".
3. Select "SATA Configuration".
4. Change "SATA Mode Selection" to "AHCI".

Try rebuilding the MBR (Master Boot Record)

Inaccessible Boot Device may occur due to a problem with MBR.

In this case, rebuilding the MBR using the method below may solve the problem.

How to repair the boot sector (MBR) and use Testdisk in Windows 10 and 11

How to use EaseUS Partition Master and solutions when it cannot be used

Repair boot sector with TestDisk

Repairing the boot sector using TestDisk may resolve the issue.

[How to repair the boot sector (MBR) using TestDisk]

1. TestDisk Download – CGSecurityObtain the software at
2. Start TestDisk.
3. Select Create.
4. Press the Enter key.
5. Select the disk you want to recover and select "Proceed".
6. Select the partition type.
7. Select "MBR Code".
8. Press the "Y" key.
9. A confirmation screen will appear, so if there is no problem, press the "Y" key.
10. Once completed, restart your computer.

Replace HDD or SSD

If you are experiencing an Inaccessible Boot Device error, replacing your HDD or SSD may resolve the issue.

If the problem is not resolved even after trying the other solutions, there is a possibility that the HDD or SSD is defective and may need to be replaced.

Recovery or clean install

If you receive an Inaccessible Boot Device error, recovery or a clean install may resolve the issue.

Recovery or clean installation will delete saved data, so please consider it as a last resort.
Also, be sure to back up your data before running it.

[Windows recovery (initialization) method]

1. Enter the Windows recovery environment (force quit twice or use a recovery drive, etc.)
2. Select "Troubleshoot".
3. Select "Reset this PC".

replace motherboard

If you encounter an Inaccessible Boot Device error and keep rebooting, your motherboard may be the culprit.

First, check the physical connection status of the motherboard.

The error may also be caused by a poor connection.
If the connection is fine and the error is caused by the motherboard, it needs to be replaced.

Causes of Inaccessible Boot Device

Possible causes of the Inaccessible Boot Device error include:

• Problems with Windows 10 and 11 updates
• Unable to access or unstable access to startup disk
• The startup disk is inaccessible or unstable due to a driver.

Problems with Windows 10 and 11 updates

If Inaccessible Boot Device occurs, an update may be affecting it.

If an update was recently performed, removing it may resolve the issue.
Uninstall updates

Unable to access or unstable access to startup disk

Inaccessible Boot Device may occur due to problems accessing the startup disk.

This includes physical defects.
Please check whether the HDD or SSD containing the OS is properly connected to the cable.
We recommend that you reconnect the SATA cable once.

The startup disk is inaccessible or unstable due to a driver.

If an Inaccessible Boot Device error occurs, it is possible that the AHCI driver is preventing you from connecting to the startup disk.
In this case, try updating the AHCI driver using the method below.

[How to update AHCI driver]

1. Boot up the recovery environment using a recovery drive etc.
2. Select "Troubleshoot".
3. Select Advanced Options.
4. Select "Startup Settings".
5. Select "Restart".
6. Select "4" using the number keys.
7. Safe mode will start.
8. Press the "Windows" key and "X" key at the same time.
9. Select "Device Manager".
10. Select "IDE ATA/ATAPI Controller".
11. Right-click on the standard SATA AHCI controller.
12. Select "Update Driver".

Is it not possible to boot in safe mode with an Inaccessible Boot Device?

When an Inaccessible Boot Device error occurs, there are cases where you can boot in safe mode, and cases where you cannot boot.

If you can start it, you can update drivers etc. from safe mode.

If Windows 10, 11 does not boot with Inaccessible Boot Device after cloning

If Inaccessible Boot Device occurs after cloning on Windows 10 or Windows 11, please check the following points.

• Check if the startup disk is correct in BIOS (UEFI)
• Check for GPT and MBR conflicts
• There is a problem with the source disk or it is incorrect.
• A problem occurred during cloning

Check if the startup disk is correct in BIOS (UEFI)

If Inaccessible Boot Device occurs after cloning, please check if the boot disk in BIOS (UEFI) is correct.

An error may occur if the startup order is incorrect.

[How to set up a boot disk for BIOS (UEFI)]

1. Boot into BIOS (UEFI).
2. Change the "Boot Device Priority" in "Boot" to the correct order.
3. Save the settings with "Exit".

Check for GPT and MBR conflicts

If Inaccessible Boot Device occurs after cloning, please check if there is a GPT or MBR conflict.

[How to check if there is a conflict with GPT or MBR]

1. Boot into BIOS.
2. Select "UEFI/BIOS Boot Mode" under "Boot".
3. If the partition is GPT, select "UEFI", if it is MBR, select "Legacy".
4. Exit the BIOS.

There is a problem with the source disk/You used the wrong source disk.

If Inaccessible Boot Device occurs after cloning, the source disk may be defective or the source disk may be wrong.

If there are bad sectors on the source disk, it may be resolved by using CHKDSK.

A problem occurred during cloning

If Inaccessible Boot Device occurs after cloning, a problem may have occurred during cloning.

In this case, you need to run the clone again and connect without any problems.

Repair and cause summary of Inaccessible Boot Device that keeps restarting in Windows 10 and 11

This time, we explained what to do if you get an "Inaccessible Boot Device" error on Windows 10 or Windows 11 and keep restarting your computer.

There are several ways to deal with the Inaccessible Boot Device error, so please try them out.

Also, be sure to take a backup before initializing or performing a clean install.