Get the fix to the 0xc0000001: A required device isn’t connected or can’t be accessed boot error message affecting Windows XP, Windows Vista, Windows 7, Windows 8, Windows 8.1 and Windows 10.

About the “0xc0000001” error

The following information on this error has been compiled by NeoSmart Technologies, based on the information gathered and reported by our global network of engineers, developers, and technicians or partner organizations.

Description and Symptoms

The error messages, alerts, warnings, and symptoms below are tied to this error.

Symptom 1: 0xc0000001 error screen on startup

The 0xc0000001 error can be caused by a wide variety of causes, with the most common one being system file corruption, or damaged memory. Alternatively, this error can also be caused by a missing or damaged SAM(Security Account Manager) system file.

0xc0000001 boot error screen

Windows failed to start. A recent hardware or software change might be the cause. To fix the problem: 

1. Insert your Windows installation disc and restart your computer. 
2. Choose your language settings, and then click "Next." 
3. Click "Repair your computer." 

If you do not have this disc, contact your system administrator or computer manufacturer for assistance. 

Status: 0xc0000001 

Info: A required device isn't connected or can't be accessed.

On newer system, another error screen is displayed instead:

0xc0000001 boot error screen

Windows Recovery Environment

Your PC couldn't start properly

A required device isn't connected or can't be accessed.

Error code: 0xc0000001

You'll need to use the recovery tool on your installation media. If you don't have any installation media like disc or USB devices, contact your system administrator or PC manufacturer.

Press Enter to try again
Press F8 for alternate boot options

Note that the exact error message may vary from case to case, but the error code for this error is always “0xc0000001”.

Alternatively, you may also see an error message right after Windows loads:

0xc0000001 boot error screen

Security Accounts Manager initialization failed because of the following error: A device attached to the system is not functioning. Error Status: 0xc0000001. Please click OK to shut down this system and reboot into Safe Mode, check event log for more detailed information.

Causes of this Error

This error has been known to occur as a result of one or more of the following:

Cause 1: SAM file is damaged

The SAM(Security Accounts Manager) file stores the user credentials data and is essential to Windows booting process. If that file is missing or corrupt, then the boot process is halted.

Cause 2: System files are damaged

Sometimes, this error may occur when the key boot-related system files become damaged because of disk write error, power outages or virus attacks.

Cause 3: File system integrity compromised

Alternatively, this error appears when the whole file system gets damaged on a grander scale for the same reasons.

Cause 4: RAM is damaged

In the worst case scenario, the PC’s memory could be permanently damaged.

Fixing “0xc000000e” on Windows

Windows Setup CD/DVD Required!
Some of the solutions below require the use of the Microsoft Windows setup CD or DVD. If your PC did not come with a Windows installation disc or if you no longer have your Windows setup media, you can use Easy Recovery Essentials for Windows instead. EasyRE will automatically find and fix many problems, and can also be used to solve this problem with the directions below.

Fix #1: Use Easy Recovery Essentials

Easy Recovery Essentials can fix many errors such as this automatically using its built-in Automated Repair option. EasyRE is currently available for Windows XP, Vista, 7 and 8 and can be downloaded and created on any PC.

  1. Download Easy Recovery Essentials. Make sure to note your Windows version (XP, Vista, 7 or 8) before you download EasyRE. This guide can help you identify what version of Windows you have installed.
  2. Burn the image. Follow these instructions on how to burn the bootable ISO image very carefully, as making a bootable CD can be tricky! Alternatively, these instructions explain how to create a bootable EasyRE recovery USB stick/drive.
  3. Boot up your PC from the Easy Recovery Essentials CD or USB you created.
  4. Once EasyRE is running, choose the “Automated Repair” option and click Continue.
    EasyRE Home

    Choose “Automated Repair” in Easy Recovery Essentials

  5. After EasyRE scans your computer’s drives, identify and select the drive letter for your Windows installation from the list, and then click on the Automated Repair button to begin.
    EasyRE displays a list of found Windows operating systems

    Choose the drive associated with the Windows installation you’re trying to repair.

  6. Easy Recovery Essentials will start analyzing the selected drive for problems. EasyRE will test for and attempt to automatically correct errors with the disk, partition, bootsector, filesystem, bootloader, and registry. No intervention is required, as EasyRE’s repair is fully automated:
    EasyRE: Automated Repair

    Easy Recovery Essentials searches for errors and makes corrections to the selected Windows installation.

  7. Once the process is complete, EasyRE will report its findings. Click on the Restart button to reboot your PC and test the changes.
  8. The “0xc0000001” error should now be fixed as your PC begins to load:
    EasyRE: Automated Repair

    Windows, booting up successfully.

You can download Easy Recovery Essentials from here.

Fix #2: Copy the SAM File from the Repair Folder

If you’re able to login into Windows, copy the SAM file from C:\WINDOWS\repair to C:\WINDOWS\system32\config. To do that, boot from a Windows Install CD, open a command prompt, and enter:

copy C:\Windows\Repair\Sam C:\Windows\System32\Config

If asked whether you want to overwrite the original file, reply “Y”(Yes).

This will remove all login credentials your Windows copy has, including username and password and revert back to the original username that was added when you installed Windows.

SAM file restored from a backup

SAM file restored from a backup

Fix #3: Run chkdsk

If the hard drive has its file integrity compromised, it is possible to use built-in Windows CHKDSK utility to scan the disk and fix the file system errors.

Here are the steps to run CHKDSK:

  1. Boot from your Windows install disc
  2. Click on Repair your computer after selecting proper language, time and keyboard input.
  3. Select the Windows installation drive, which is usually C:\, and click Next
  4. Choose Command Prompt when the System Recovery Options box appears
  5. Write the following command and press Enter afterwards:
    chkdsk C: /f

    Replace C: with the letter of the driver where Windows is installed.

Here is an example of what the PC’s console output should look like once the chkdsk.exe is complete:

Chkdsk utility results screen

Chkdsk utility results screen

Fix #4: Check RAM

Check if you recently added any new RAM modules. Users have reported that a new RAM module was the actual cause for this boot error. Replace the RAM modules to see if they are causing this error to appear.

Fix #5: Run sfc /scannow

On Windows Vista and Windows 7, it is possible to use the built-in Windows SFC(system file checker) tool to automatically scan a computer’s system files and repair them if necessary.

Here are the steps to run SFC:

  1. Boot from your Windows install disc
  2. Click on Repair your computer after selecting proper language, time and keyboard input.
  3. Select the Windows installation drive, which is usually C:\, and click Next
  4. Choose Command Prompt when the System Recovery Options box appears
  5. Write the following command and press Enter afterwards:
    sfc /scannow /offbootdir=D:\ /offwindir=D:\Windows\

    Replace D: with the letter of the driver where Windows is installed, and D:\Windows with the Windows folder location.

Here is an example of what the PC’s console output should look like once the sfc.exe scan is complete and missing files are successfully restored:

System files restored by the SFC utility

System files restored by the SFC utility

Fix #6: Check the HDD

If the error is caused by damaged hard disk cables, try any of the following tips to fix the error:

  • Try a different port for the SATA/IDE cables
  • If you have more than 1 HDD, leave only the HDD with Windows installed and test multiple SATA/IDE ports and cables

The “A disk read error occurred” error can appear if:

  • The SATA/IDE cables are damaged
  • The SATA/IDE ports of your hard disks are damaged

If the HDD cables and ports are not damaged, the issue can also be from the hard disk itself.

To test if your hard disk is failing or it’s already failed, use Easy Recovery Essentials’ Automated Repair. Automated Repair process will report any issues found with your hard disk or RAM memory:

  1. Download Easy Recovery Essentials
  2. Burn the ISO Image. Follow our instructions on how to burn a bootable ISO image. If you’d like to have a recovery USB instead, follow our instructions on how to make a recovery USB.
  3. Boot into Easy Recovery Essentials
  4. Select Automated Repair
  5. Click Continue and wait for the Automated Repair process to finish. Automated Repair process will report any issues found with your hard disk or RAM memory:

    EasyRE: HDD is failing

To download Easy Recovery Essentials, click here.

Fix #7: Use Windows Startup Settings

  1. Restart your computer
  2. Press SHIFT + F8 when booting to open the Recovery screen
  3. Select the Advanced repair options
  4. Go to Troubleshoot and then Advanced Options
  5. Select Windows Startup Settings
  6. Click Restart
Startup Settings screen

Startup Settings screen

More Information

Linked Entries

Support Links

Applicable Systems

This Windows-related knowledgebase article applies to the following operating systems:

  • Windows XP (all editions)
  • Windows Vista (all editions)
  • Windows 7 (all editions)
  • Windows 8 (all editions)
  • Windows 8.1 (all editions)
  • Windows 10 (all editions)

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