Get the fix for the error Disk Signature Collision on Windows XP, Windows Vista, Windows 7, Windows 8 and Windows 10.

About “Disk Signature Collision

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: “Disk is offline” error message on disk management screen

A disk signature is unique four-byte identifier in a disk’s MBR(Master Boot Record), which is written to the first sector of a disk. It is used by the operating system to differentiate between storage devices on a computer. However, if two different drives’ signatures become identical, then one of these drives becomes marked as offline automatically, and its data becomes inaccessible. Here is a screenshot of a Windows Disk Management utility screen with a duplicate signature drive that is offline:

Disk is offline, signature collision error screen

The disk is offline because it has a signature collision with another disk that is online

Note that if a boot drive becomes offline because of a signature collision, then the PC becomes unable to boot properly, and a 0xc000000e error is displayed on startup. Also note that starting with Windows Vista, the system automatically saves the disk signatures and letters of their drives in the registry, at HKLM\SYSTEM\MountedDevices – be sure to check that registry hive if you want to change letters assigned to your drives or you want to restore the previously changed drive signature.

Causes of this Error

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

Cause 1: Disk signature collision

The disk signatures are used by an operating system to differentiate storage devices and access data. If the system detects that there are two different drives with the same signature available, it disables one of these drives automatically.

Fixing “Disk is offline” 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: Change disk signature and set disk online with Easy Recovery Essentials

Easy Recovery Essentials’ one-click automated system repair corrects issues caused by drive signature collisions for boot drives by changing a boot drive’s signature and setting it back online. This is done automatically as part of the automated repair process, and requires no manual action or user intervention.

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 “disk signature collision” 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: Use Windows’ built-in Automatic Repair

The Windows Automatic Repair can be used to detect a disk signature collision error and fix it automatically. Here are the steps to access the Automatic Repair from an install disc:

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.

Startup Repair is an automated diagnosis and repair tool that is available from the Windows setup disc and can be used to find and repair some common problems. More information about how Startup Repair operates and what it does can be found in our knowledgebase. The following steps will initiate Startup Repair from the Windows setup disc:

Unable to boot into the Windows setup CD?
See our guide on setting up a PC to boot from the CD or DVD for troubleshooting and more detailed instructions.

  1. Insert your Windows installation DVD into your PC’s CD-ROM drive,
  2. Fully power down your PC, and make sure it has fully shut off,
  3. Power up your PC,
  4. Press any key when you see “Press any key to boot from CD or DVD..”
  5. Click the link titled “Repair your computer” in the bottom-lefthand corner, after first selecting your language and keyboard options.
    Windows 7 setup Install Now dialog, with repair your computer link
  6. Wait for Startup Repair to scan your PC for Windows installations, then select your install from the list it shows:
    Startup repair lists available operating systems to repair.
  7. Choose “Startup Repair” from the list of available recovery options to begin:
    Startup Repair lists all available recovery options, choose a recovery tool
  8. Startup Repair will begin scanning your installation for known issues and will attempt a repair, if possible.
    Windows Startup Repair is searching for problems

Here is an example of what the PC’s startup repair should look like once the disk signature collision error is fixed:

Disk signature error collision fixed by Windows Startup Repair

Disk signature collision error fixed by Windows Startup Repair

Fix #3: Change disk signature with Disk Management

To fix a disk signature collision error from Windows using Disk Management, follow these steps:

  1. Start the PC
  2. Click Start
  3. Enter diskmgmt.msc and press Enter to open Disk Management
  4. Right-click the disk that’s marked as Missing or Offline
  5. Click Online
Disk signature collision error fixed in Disk Management

Disk signature collision error fixed in Disk Management

Fix #4: Change disk signature with diskpart

If Windows doesn’t boot properly and Startup Repair is unable to fix the signature collision error, it is also possible to change the disk signature manually from Windows Recovery Console. Follow these steps to do it:

  1. Boot from the 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 to open Diskpart:
    diskpart
  6. Write the following command to view all available disks and press Enter afterwards:
    list disk
  7. Write the following command and press Enter afterwards to select an offline disk:
    select disk 0

    Where 0 is the disk’s number.

  8. Then, write the following commands, pressing Enter after each to change the disk’s signature and set it online:
    uniqueid disk ID=1234ABCD
    online disk
  9. Then, write the following command to ensure that the disk was set online correctly:
    list disk

Here is an example of what the PC’s console output should look like once the disk signature was changed successfully and the disk is back online:

Disk signature collision error fixed in diskpart

Disk signature collision error fixed in diskpart

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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