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Get the fix for the "<strong>Boot critical file is corrupt</strong>" error for <strong>Windows Vista, Windows 7, Windows 8 </strong>and<strong> Windows 8.1</strong>
<h2>About "Boot critical file is corrupt"</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: Startup repair fails with message "Boot critical file $file is corrupt"</h3>
The error "Boot critical file is corrupt" is displayed when Startup Repair fails to correct problems with a non-booting PC.

In particular, this message indicates that Startup Repair identified that the file in question was determined to be damaged, corrupted, or infected. If you are using Startup Repair from a recovery-only CD (typically 120 - 160 MiB), it will not have the file repair option needed.

Windows uses <a href="#todo_digitalsignatures">digital signatures</a> to identify if system files have been damaged or modified by anyone since the date Microsoft digitally "signed" the files. Discrepancies in the file signature indicate that a file has been modified, infected, or tampered with by unauthorized persons or software.

When attempting to use the automated repair feature of Startup Repair, it attempts to repair your PC but fails. Clicking to view the contents of Startup Repair's "Diagnosis and repair details" reveals the error to be "Boot critical file $file is corrupt" with one or more failed repair attempts, where $file is the name of a critical system file needed for Windows to start up. Depending on the file and the exact origins of the repair CD, you may then see one or more messages pertaining to recovery methods attempted.

Example message:

<a href="/wiki/wp-content/uploads/sites/5/2013/08/Boot-critical-file-is-corrupt.png"><img class="alignnone wp-image-1485" src="/wiki/wp-content/uploads/sites/5/2013/08/Boot-critical-file-is-corrupt.png" alt="Boot critical file C:\Windows\system32\drivers\fileinfo.sys is corrupt Repair action: File repair Result: Failed. Error code = 0xa Time taken = 1529 ms Repair action: System Restore. Result: Failed. Error Code = 0x1f" width="402" height="307" /></a>
<pre>Test Performed:
---------------------------
Name: System boot log diagnosis
Result: Completed successfully. Error code =  0x0
Time taken = 0 ms

Root cause found:
---------------------------
Boot critical file C:\Windows\system32\drivers\fileinfo.sys is corrupt

Repair action: File repair
Result: Failed. Error code = 0xa
Time taken = 1529 ms

Repair action: System Restore.
Result: Failed. Error Code = 0x1f

Repair action: System files integrity check and repair.
Result: Failed. Error Code = 0x490</pre>
<h3>Known files affected</h3>
As mentioned above, the error "Boot critical file is corrupt" is not limited to a single system file. Our field technicians have identified that this error could present itself with any of the following files, amongst others:
<ul>
 	<li>C:\CI.dll</li>
 	<li>C:\Windows\system32\ntoskrnl.exe</li>
 	<li>C:\Windows\system32\ntkrnlpa.exe</li>
 	<li>C:\Windows\system32\kdcom.dll</li>
 	<li>C:\Windows\system32\drivers\fileinfo.sys</li>
 	<li>C:\Windows\system32\drivers\vmbus.sys</li>
 	<li>C:\Windows\system32\drivers\megasr.sys</li>
 	<li>C:\Windows\system32\drivers\iastor.sys</li>
 	<li>C:\Windows\system32\drivers\sshrmd.sys</li>
 	<li>C:\Windows\system32\drivers\atapi.sys</li>
 	<li>C:\Windows\system32\drivers\compbatt.sys</li>
 	<li>C:\Windows\system32\drivers\ecache.sys</li>
 	<li>C:\Windows\system32\drivers\hal.dll</li>
 	<li>C:\Windows\system32\drivers\intelide.sys</li>
 	<li>C:\Windows\system32\drivers\aswvmm.sys</li>
 	<li>C:\Windows\system32\drivers\acpi.sys</li>
 	<li>C:\Windows\system32\drivers\tpm.sys</li>
 	<li>C:\Windows\system32\drivers\tcpip.sys</li>
</ul>
The list above is not exhaustive and this error may appear with files other than those mentioned above.
<h2>Causes of this Error</h2>
This error has been known to occur as a result of one or more of the following:
<h3>Cause 1: Corrupt Windows volume</h3>
Corruption of the system partition on a Windows PC can cause this error to present.

If the drive Windows is installed to suffers filesystem corruption for any reason (e.g. unsafe shutdown, sudden power loss, etc.) the data on the drive may no longer be read correctly and will trigger the above integrity alert.

Corruption of the boot partition is known to occur on both NTFS and FAT32 partitions.
<h3>Cause 2: Corruption of system files</h3>
The files named above (and other files in the \Windows\system32\ directory) are critical components of Windows. If the files are inadvertently replaced or overwritten by other data due to bugs in recently installed computer software or due to user error (for example, during system backup), the "boot critical file is error" may present.
<h3>Cause 3: Virus infection</h3>
If a Windows computer has become infected by a virus, it may attempt to inject itself or other malicious code into one or more critical system files. Corruption of any of the digitally signed drivers or libraries (files with extensions .sys or .dll) can cause your PC to fail to boot and this error to be shown by Startup Repair. Of particular note is that viruses may infect/inject a file that is <i>not</i> a critical Windows system/boot file and then set up your PC to load this file on boot. For example, any "boot critical file is corrupt" errors indicating a corrupt C:\CI.dll are guaranteed to be the result of system infection as this file is not normally part of the Windows startup process.
<h3>Cause 4: Rootkits</h3>
Viruses, spyware, or other malware on your PC as well as DRM software attempting to prevent copyright infringement and IP violation may patch or modify core system files in an attempt to cloak their existence from antivirus or encryption circumvention software on your PC. Changes to core system files for this or any other reason will trigger the "Critical boot file is corrupt" error.
<h2>Fixing "Boot critical file is corrupt" on Windows</h2>
[setupcd]
<h3>Fix #1: Scan the Windows drive for corruption</h3>
[partial name="partial_chkdsk"]
<h3>Fix #2: Scan for viruses with Easy Recovery Essentials</h3>
[partial name="partial_easyre_av"]
<h3>Fix #3: Scan for corrupted files</h3>
[partial name="partial_sfc"]
<h2>More Information</h2>
<h3>Linked Entries</h3>
<ul>
 	<li><a href="https://neosmart.net/wiki/chkdsk/">chkdsk</a></li>
 	<li><a href="https://neosmart.net/wiki/sfc/">sfc</a></li>
</ul>
[partial name="partial_moreinfo" versions="vista,7,8,server2008,server2012"]