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<span style="line-height: 1.5">Get the fix for the error <strong>Disk Signature Collision</strong> on <strong>Windows XP,</strong> <strong>Windows Vista,</strong><strong> Windows 7, Windows 8 </strong>and <strong>Windows 10</strong>.</span>
<h2>About "<strong>Disk Signature Collision</strong>"</h2>
[kbintro]
<h3><span id="Description_and_Symptoms">Description and Symptoms</span></h3>
The error messages, alerts, warnings, and symptoms below are tied to this error.
<h3>Symptom 1: "Disk is offline" error message on disk management screen</h3>
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:

<a href="https://neosmart.net/wiki/wp-content/uploads/sites/5/2015/03/disk-is-offline-signature-collision.png"><img class="alignnone size-large wp-image-4370" src="https://neosmart.net/wiki/wp-content/uploads/sites/5/2015/03/disk-is-offline-signature-collision-1024x768.png" alt="Disk is offline, signature collision error screen" width="980" height="735" /></a>
<pre>The disk is offline because it has a signature collision with another disk that is online</pre>
Note that if a boot drive becomes offline because of a signature collision, then the PC becomes unable to boot properly, and a <a href="http://neosmart.net/wiki/0xc000000e/">0xc000000e</a> 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 <b>HKLM\SYSTEM\MountedDevices </b>- 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.
<h2>Causes of this Error</h2>
This error has been known to occur as a result of one of the following causes:
<h3>Cause 1: Disk signature collision</h3>
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.
<h2>Fixing “Disk is offline<span id="Fixing_8220Fatal_INT18_Boot_failure8221_on_Windows">” on Windows</span></h2>
[setupcd]
<h3>Fix #1: Change disk signature and set disk online with Easy Recovery Essentials</h3>
<span class="message_body">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.</span>

[easyre error="disk signature collision" bootscreen="xp-vista-7-8-10"]
<h3></h3>
<h3>Fix #2: <span id="Fix_4_Use_Windows_built-in_Automatic_Repair">Use Windows’ built-in Automatic Repair</span></h3>
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:

<span style="line-height: 1.5">[setupcd]</span>

[partial name="partial_startup_repair"]

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

[caption id="attachment_4373" align="alignnone" width="800"]<a href="https://neosmart.net/wiki/wp-content/uploads/sites/5/2015/03/disk-signature-restored.png"><img class="wp-image-4373 size-full" src="https://neosmart.net/wiki/wp-content/uploads/sites/5/2015/03/disk-signature-restored.png" alt="Disk signature error collision fixed by Windows Startup Repair" width="800" height="600" /></a> Disk signature collision error fixed by Windows Startup Repair[/caption]
<h3>Fix #3: Change disk signature with Disk Management</h3>
To fix a disk signature collision error from Windows using Disk Management, follow these steps:
<ol>
 	<li>Start the PC</li>
 	<li>Click <strong>Start</strong></li>
 	<li>Enter <strong>diskmgmt.msc </strong>and press <strong>Enter</strong> to open <strong>Disk Management</strong></li>
 	<li>Right-click the disk that's marked as <strong>Missing</strong> or <strong>Offline</strong></li>
 	<li>Click <strong>Online</strong></li>
</ol>
[caption id="attachment_4374" align="alignnone" width="800"]<a href="https://neosmart.net/wiki/wp-content/uploads/sites/5/2015/03/diskmgmt_msc-online-disk.png"><img class="wp-image-4374 size-full" src="https://neosmart.net/wiki/wp-content/uploads/sites/5/2015/03/diskmgmt_msc-online-disk.png" alt="Disk signature collision error fixed in Disk Management" width="800" height="600" /></a> Disk signature collision error fixed in Disk Management[/caption]
<h3>Fix #4: Change disk signature with diskpart</h3>
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:
<ol>
 	<li>Boot from the Windows install disc</li>
 	<li>Click on <strong>Repair your computer</strong> after selecting proper language, time and keyboard input.</li>
 	<li>Select the Windows installation drive, which is usually <code>C:\</code>, and click <strong>Next</strong></li>
 	<li>Choose Command Prompt when the System Recovery Options box appears</li>
 	<li>Write the following command and press <kbd>Enter</kbd> afterwards to open Diskpart:
<pre>diskpart</pre>
</li>
 	<li>Write the following command to view all available disks and press <kbd>Enter</kbd> afterwards:
<pre>list disk</pre>
</li>
 	<li>Write the following command and press <kbd>Enter</kbd> afterwards to select an offline disk:
<pre>select disk 0</pre>
Where 0 is the disk's number.</li>
 	<li>Then, write the following commands, pressing <kbd>Enter</kbd> after each to change the disk's signature and set it online:
<pre>uniqueid disk ID=1234ABCD</pre>
<pre>online disk</pre>
</li>
 	<li>Then, write the following command to ensure that the disk was set online correctly:
<pre>list disk</pre>
</li>
</ol>
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:

[caption id="attachment_4375" align="alignnone" width="800"]<a href="https://neosmart.net/wiki/wp-content/uploads/sites/5/2015/03/diskpart-signature-fix.png"><img class="wp-image-4375 size-full" src="https://neosmart.net/wiki/wp-content/uploads/sites/5/2015/03/diskpart-signature-fix.png" alt="Disk signature collision error fixed in diskpart" width="800" height="600" /></a> Disk signature collision error fixed in diskpart[/caption]
<h2>More Information</h2>
<h3>Linked Entries</h3>
<ul>
 	<li><a href="https://neosmart.net/wiki/diskpart/">diskpart</a></li>
 	<li><a href="http://neosmart.net/wiki/0xc000000e/">0xc000000e</a></li>
</ul>
[partial name="partial_moreinfo" versions="xp,vista,7,8,10"]