By Delia / Last Updated September 2, 2020

A required device isn’t connected or can’t be accessed

“Whenever I reboot my pc I get the error ‘A required device isn't connected or can't be accessed’ along with the error code 0xc000000f, I can't boot into windows 10 unless I push F9, F9 is the option to boot into a different OS but it boots into my existing windows 10 installation. Is there any way I can fix this?”

As in this case, if your computer suddenly shows a blue screen with the following error message: Your PC/Device needs to be repaired. A required device isn't connected or can’t be accessed (0xc00000f), it’s most likely due to BCD missing, system file corruption or data cable damage.

No matter what the reason is, you’ll probably find none of the solutions in the lower left corner work after a few attempts, neither can you launch Windows to take common measures. So how to fix it effectively?

Error Code 0xc000000f

How to fix required device isn’t connected or cannot be accessed?

Depending on the specific cause of 0xc00000f, there are several ways to fix required device isn’t connected or cannot be accessed in Windows 10.

From Method 2 to Method 6 you are required to enter Windows Recovery Environment (WinRE) at first, here are the 2 approaches:

Approach 1. Insert an installation disc or recovery drive, then wait for a while and select your language, region, etc. in Windows Setup, click Next > Repair your computer.

Approach 2. Hold your power button to turn down the PC. Power it on and then power it off once Windows has started (e.g. the manufacturer’s logo appears). Again, power it on and off. On the third-time boot, you’ll enter WinRE.

Method 1. Remove and check external devices

Before doing anything else, try removing all the connected devices from your computer, and rebooting it to rule out the possibility that the problem is caused by a recently added device.

If your computer boots normally like this, you can reconnect these devices one by one and start the computer after each. That way you can find out which device is the root of error 0xc00000f.

If you are pretty sure all your devices and cables are OK, try other solutions as following.

Method 2. Perform Startup Repair

Startup Repair can solve some common startup problems in Windows. If you can’t boot your PC normally, you can try this feature in WinRE.

Step 1. Click Troubleshoot > Advanced options.

Step 2. Choose Startup Repair. It will take some time to complete the repair.

Step 3. Restart your PC to see if the error “a required device isn't connected or can't be accessed” still exists.

If this feature doesn’t work, learn more about how to fix Windows 10 Startup Repair.

Startup Repair

Method 3. Perform System Restore

If you’ve created a restore point in Windows 10 when there’s no such an error, you can simply fix it by restoring system to a normal state.

Step 1. In WinRE, click Troubleshoot > Advanced options.

Step 2. Choose System Restore, wait for the preparing to complete.

Step 3. Log in your account if required. Then the System Restore wizard will pop out.

Step 4. Click Next to select the restore point, and hit Next to continue.

Step 5. Click Finish to start restoring. After that, restart your computer to check if your PC/device still needs to be repaired.

You can check more detailed steps in how to system restore from boot in Windows 10/8/7.

System Restore Pe

Method 4. Rebuild BCD with command prompt

BCD refers to boot configuration data, which largely determines whether you can boot Windows properly. So if you encounter the problem saying your PC needs to be repaired and a required device isn't connected or can’t be accessed, one effective way is to rebuild BCD with command prompt.

Step 1. In WinRE, click Troubleshoot > Advanced options > Command Prompt.

Step 2. You might be asked to log in your account at first. Then type following commands and press Enter key after each.

Bootrec /fixmbr

Bootrec /fixboot

Bootrec /scanos

Bootrec /rebuildbcd

Step 3. Enter A to add the installation to the boot list, then press Enter.

Step 4. Quit command prompt and click Continue to launch Windows 10.

Note: after executing bootrec /scanos, if you receive this prompt “Total identified Windows installations”, please enter following commands before rebuilding BCD:

bcdedit /export C:\bcdbackup


cd boot

attrib bcd -s -h –r

ren C:\boot\bcd bcd.old

Enter Command

Method 5. Check disk and system file

Similarly, you can run command prompt to detect disk and system file corruption. It requires you to enter WinRE as well.

Step 1. Click Troubleshoot > Advanced options > Command Prompt.

Step 2. Type the command sfc /scannow to check system file, then press Enter key and wait for the process to end.

Step 3. Type CHKDSK C: /f /r and press Enter key to execute it.

Step 4. When the process is complete, restart your computer.

System File Checker

Method 6. Set active partition in Command Prompt

A required device isn’t connected or can’t be accessed in Windows 10 could be caused by setting active partition incorrectly. To fix, you can try following steps in WinRE:

Step 1. Go to Troubleshoot > Advanced options > Command Prompt.

Step 2. Type following commands. Remember to press Enter after each.


list disk

select disk 0 (0 refers to the number of your system disk)

list partition

select partition 1 (1 refers to the number of your system partition)

Step 3. Then quit the command prompt and restart your computer.

List Disk

Method 7. Disable Secure Boot option

Secure Boot ensures your PC only uses firmware trusted by the manufacturer during startup. However, it also causes boot problems sometimes due to hardware misconfiguration. To fix the error that a required device isn't connected or can’t be accessed in Windows 10, one possible approach is to disable Secure Boot.

Step 1. Press the certain key to enter BIOS settings. The key could be Delete, F2, F10, F12, etc. If you are not sure, search it on the Internet or refer to the user manual.

Step 2. Find Secure Boot option and disable it. It’s usually under Security or Boot tab.

Step 3. Save the settings and quit BIOS. Your computer will reboot automatically.

Disable Secure Boot

Method 8. Reset BIOS settings from boot

Corrupted or incorrect BIOS settings sometimes may lead to the error that a required device isn't connected or can’t be accessed in Windows 10. In this case, you could reset the BIOS settings.

Step 1. Enter BIOS settings by pressing certain key.

Step 2. Press F9 key to load the factory default settings automatically, then confirm the operation

Step 3. Save the changes and exit BIOS, which can also be performed by pressing F10.

Reset Bios Settings

Precaution against system errors

Every Windows user should have experienced the dilemma that the computer can't boot due to a system error, and the fact of not being able to log in to Windows makes the situation even more complicated, because you can't fix it with normal means.

How could you get out of this mess? Calling professionals or reinstalling the computer can usually take effect, but you won’t want to do it every single time.

Therefore, you’d better get in the habit of creating system images on a regular basis so as to restore Windows to an error-free state when needed.

If you haven't done this before, it’s not late to start it once you've solved the problem.

The built-in backup feature in Windows enables you to create a restore point, but it has limited functionality with less flexibility. For people like me who often forget to do backups or don't bother to operate it manually, a tool that can automatically and quickly back up system would be more practical.

Take AOMEI Backupper Standard as an example, it’s a backup & restore software with rich options including schedule modes. Not only system backup, you can use it to backup specific files, migrate operation system, clone disk, sync folders and so on. Most of all, it’s a totally freeware so you can give it a shot without concern.

Download Freeware Win 10/8.1/8/7/XP
Secure Download

How to perform system backup automatically with AOMEI Backupper:

Step 1. Launch the software. Navigate to Backup and choose System Backup.

System Backup

Step 2. You don’t need to specify the source directory since it’s automatically detected. Just select a destination path.

For future use in case of computer crashes, you can back it up to NAS, cloud drive or external devices.

Start Backup To Nas

Step 3. Click Schedule on the bottom to set up automatic backup. Then hit Start Backup.

Optionally, you can edit Task Name, manage settings in Options, or set up Scheme to delete older backups.

Schedule Settings General

Step 4. Wait for the backup to complete, click Finish.

System Backup Complete

Step 5. To restore the created system image, you just need to click Restore > Select Image File and locate the image to Start Restore.

Select Image File

It’s also recommended to create a bootable disc or USB with this software. Thus you can use it to start the unbootable computer, and restore the system to a normal state under Windows PE.

What else to expect:

  • Rich auxiliary functions: you can comment on the backup, choose backup mode, compress image, split image, etc. in backup Options.

  • Flexible schedule modes: in addition to general options Daily, Weekly and Monthly, you can also upgrade to AOMEI Backupper Professional to enjoy Event triggers and USB plug in.

  • Scheme to delete older backups automatically: if you have limited space to store system images, this feature can automatically delete older backups with the rule you set. It’s supported by advanced editions.


To fix required device isn’t connected or cannot be accessed in Windows 10, there are many solutions you can try. But none of them ensures it won’t happen again since Windows is sophisticated and prone to problems. The best way to protect operation system is to develop a good backup habit and create system images on regular basis, and an effective tool can greatly simplify the process - such as AOMEI Backupper.

With its rich and powerful functions, you can prevent a lot of system errors such as Windows 10 reset failed, Windows 10 BCD file missing, Windows 10 Error Loading Operating System, etc.