## Thursday, January 12, 2012

### Troubleshooting 0xc000000f - Boot Failed, Inaccessible Device

From time to time an error occurs with Windows that does not result in a blue screen, but the system is unable to boot.. One of those cases is when the Windows Boot Manager Displays the following message:

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

1. Insert the Windows installation disk and restart your computer.
2. Choose your language settings, and click 'Next'

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

Status: 0xc000000f

Info: The boot selection failed because a required device is inaccessible"

Error 0xc000000f in this case is STATUS_NO_SUCH_FILE:

# for hex 0xc000000f / decimal -1073741809 :
STATUS_NO_SUCH_FILE                                  ntstatus.h
# The file %hs does not exist.
USBD_STATUS_NOT_ACCESSED                             usb.h
# 2 matches found for "c000000f" 

In my testing and research of this issue, this issue occurs when the boot partition becomes corrupted and the Windows boot manager cannot successfully access the volume that Windows is installed on (In my case I mangled the NTFS boot sector with a Linux Live CD). Repair of this issue is fairly straightforward (as long as the volume is still relatively uncorrupted). First, boot off of DVD media or USB media for Windows and access the repair utilities (by clicking on "Repair your computer".

In this case, the system partition (the one containing the boot loader) is still in working order and the recovery tools can identify that there is supposed to be a Windows installation on the second partition (labeled D: in this example). The oddity is that the partition size is reported as 0 MB (when it is actually 39 GB). For most users, using startup repair at the tools screen will allow this issue to be automatically found and resolved. For more advanced users, access the command prompt from the tools selection.

Examine the available volumes with diskpart (using the list volumes command). The system volume is labeled "System Reserved" and there is a 39 GB RAW volume (this should actually be NTFS). Like most filesystem corruption, try a chksdk -r -f on the correct drive letter (in this case, D:).

The chkdsk identified the corruption in the volume and repaired it as well as it could. The main error reported in this case:

"The first NTFS boot sector is unreadable or corrupt."

Other errors involving indexes, the USN journal, and the master file table (MFT) are identified and corrected.

Repairing the filesystem allows the system to boot normally, but it is possible that there is still additional corruption that needs to be identified and corrected before Windows can boot properly (possibly missing/corrupt files, sections of registry, etc...). Performing an offline integrity verification may help with this. In some cases the damage is too extensive and the recovery tools included with Windows may not be sufficient to return the system to a functional state. In this case, the options are restoring from backup (if one is available) and reinstalling Windows. Performing the filesystem repair above may be enough to allow any personal files to be recovered using this rescue procedure.

After the data is rescued/backed up, it is important to identify the cause of the corruption (if possible). This might be anything from a virus to a hardware issue. In the case of a hardware issue, the system memory (RAM) and the hard drive should be checked for issues.

Windows Crash Dump Analysis
Perform an Offline System Integrity Verification
Rescuing Files From a Damaged System
Troubleshooting Memory Errors
How to Detect a Failing Hard Drive

1. What do I do if I get the above error message, but I don't have my windows installation disc? I have a netbook by HP and it didn't come with any softwar or a CD/DVD Rom.

1. You can download the trial version from Microsoft and use the recovery console on that version.

2. Hello!
What if there's no other option to get out of this screen? I have the disk but no changes after I inserted the disk.