How to Fix the Inaccessible Boot Device Error in Windows 10

INACCESSIBLE_BOOT_DEVICE errors are often hard to diagnose because many problems could cause them. They usually result in a Blue Screen of Death that doesn't go away until you address the issue.

It often appears after you've made a recent change to the computer, whether software or hardware. You could also see it during a Windows installation. It usually triggers an automatic reboot and maybe even an automatic repair attempt by Windows.

The message that precedes the error often looks like this:

Your PC ran into a problem that it couldn't handle, and now it needs to restart.

How to Fix the Inaccessible Boot Device Error in Windows 10

Although this is a common error, it doesn’t have a single reason behind it. There are several things you can try to get rid of it and boot back into Windows. Follow these steps in order—they’re listed here by the ease of use—and reboot after each one to check if it was successful. 

1. Restart the computer. A simple reboot is sometimes all that’s necessary.

   If you can’t access a restart button on the screen due to the error, hold down the physical power button for a few seconds until it shuts down, and then press it again to power the computer back on.

2. Undo any recent changes made to the computer. If the INACCESSIBLE_BOOT_DEVICE error appeared after an obvious change, reversing it will most likely be the fix.

   Depending on your situation, the solution might be to remove recently installed hardware, uninstall a program, roll back a driver, or unplug a new USB device.

   If undoing the recent change resolves the error, dig into that thing specifically. For example, if your solution was to uninstall a Windows update, you might need to pause Windows Update for a while to provide time to address the problem before it gets auto-installed again.

3. Using System Restore is another way to undo recent system changes. Try this if the previous step was unhelpful.

   You're most likely locked out of your desktop due to the error. If you can't get into Safe Mode to run System Restore, find it by booting to the Advanced Startup Options menu. The ASO menu is useful for some of the steps below, too.

   If you can't get System Restore to work, there's a step later in this guide (step 9) that could still be helpful. It walks through how to restore some Windows Registry backups.

4. Update any missing or outdated drivers. Usually, drivers related to the hard drive that are corrupt or missing would cause the INACCESSIBLE_BOOT_DEVICE error, so looking there first would be wise.

   If you're not sure where to start, use a tool that updates the drivers for you. We highly recommend Driver Booster for this.

5. Select Troubleshoot from the ASO menu and go to> Advanced options > Startup Repair to run an automatic repair. Sometimes, Windows will fix the BSOD error this way without much intervention from you.

6. If Startup Repair didn't work, try Troubleshoot > Advanced options > System Image Recovery, also from the ASO menu. This feature will restore Windows from a system image backup (if you have one).

7. The Advanced Startup Options menu also lets you access Command Prompt. Go to Troubleshoot > Advanced options > Command Prompt, and then do this:

   1. Change the working directory to the Windows folder by typing c: followed by Enter.
   2. Type dir and make sure you see some Windows folders. If not, try d: and then dir again, and check that folder.

   Once you're working out of the correct drive, run the chkdsk command by typing chkdsk /r.

   If you can't access the ASO menu, open Command Prompt as admin via Safe Mode to run this command.

8. Boot to BIOS and change the SATA mode setting to be either IDE or AHCI (whichever it currently isn't). Some users have had luck correcting the BSOD by switching this mode, but it probably will only work if you recently made a BIOS change to cause this to happen, like if you just updated BIOS.

   To get there, look for an Integrated Peripherals area of the settings. It might be under an Advanced section.

9. Use Command Prompt to restore some registry files from a backup. This process is quite involved because we need to go through two sets of steps:

   This process might look daunting, but you could join other users who have had luck fixing this BSOD by completing these instructions in order. Be sure you’ve left this as the penultimate step before the more drastic solution in step 10.

   Back Up Five Items

   First, we'll back up the currently used data in case something goes wrong:

   1. Boot to the ASO menu if you’re not already there.
   2. Go to Troubleshoot > Advanced options > Command Prompt.
   3. Log in to the local user account if asked.
   4. Enter c: or d:, depending on the drive letter assigned to Windows. If you're not sure, see step 7 above.
   5. Enter this: cd windows\system32\config\regback
   6. Enter dir and confirm that the items listed don’t have a zero value. If they do have a zero value, skip these steps entirely and move on to step 8 below.
   7. Enter cd.. to return to the "config" folder.
   8. Back up these five items by renaming them. Enter the command as it's written here, press Enter, and then do the same for the rest of the commands (note that each of these lines has just two spaces):
   • ren default default.old
   • ren sam sam.old
   • ren security security.old
   • ren software software.old
   • ren system system.old

   Copy the Older Ones

   Now that the originals have been isolated, we can restore some older backups to see if that fixes the error:

   1. Return to the "regback" folder: cd regback
   2. Copy all the data from "regback" into "config" (use a space before the first asterisk and after the second one): copy *.* ..
   3. When you see the 5 file(s) copied message, exit Command Prompt.
   4. On the ASO menu, choose Continue to attempt to start Windows 10.

10. Your last option is to reset Windows 10. During this process, you can choose to keep your files or remove everything. Either way, you'll get a refreshed set of operating system files, and that should be enough to clear away the INACCESSIBLE_BOOT_DEVICE BSOD error.

Need More Help?

If you're not interested in fixing this problem yourself, see How Do I Get My Computer Fixed? for a complete list of your support options. It also includes help with everything along the way like figuring out repair costs, getting your files off, choosing a repair service, and a lot more.