Showing posts with label ahci. Show all posts
Showing posts with label ahci. Show all posts

Thursday, February 24, 2011

Windows 7 Service Pack 1 Boot Failure

Windows 7 SP1 has been released, but upon installing it, I found my system no longer boots into Windows. I get the BLACK screen of death, with the cursor flashing helplessly in the upper-left corner and no hard drive activity.

The dreaded BLACK screen of death, complete with animated cursor!


There were no obvious issues during the installation of the service pack, so I'm going to try using the BOOTREC utility in the Windows Recovery Environment in case some aspect of the service pack install, or some weird twist of fate, decided to damage the master boot record rendering my system unusable, for now.

Please feel free to share your own Windows 7 SP1 experience, whether good, bad, or ugly!


-= UPDATE =-

As I inserted my Windows 7 disc and rebooted, ready to attempt a repair through the recovery environment, I remembered something.


Before updating to Windows 7 SP1, I made a change on my system to enable AHCI (Advanced Host Controller Interface), which enables two of the best features of SATA, hot swapping and native command queueing. I'd just recently replaced the last of my old IDE hard drives and went full SATA.

To see whether this made a difference, I entered my system BIOS and changed the setting for "Configure SATA as" from IDE to AHCI, and then rebooted.




No more black screen
, my system successfully booted into Windows! 


Here are the steps I'd used originally to enable AHCI:
  1. Exit all Windows-based programs.
  2. Click Start, type regedit in the Start Search box, and then press ENTER.
  3. If you receive the User Account Control dialog box, click Continue.
  4. Locate and then click the following registry subkey:

        HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci

  5. In the right pane, right-click Start in the Name column, and then click Modify.
  6. In the Value data box, type 0, and then click OK.
  7. On the File menu, click Exit to close Registry Editor.

However
I stumbled upon a Microsoft support article (922976) which is slightly different in that it specifies an additional registry key that may be modified in order to enable AHCI.

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV


In my system's registry, the subkey value for Msahci I had changed to 0, but IastorV was still set to its default value, 3. I changed the latter so that both subkey values are set to 0, then rebooted, entered the BIOS, and this time changed the SATA setting from IDE back to the desired AHCI, saved changes, and rebooted once more.

Now, my system appears to be back to normal.
From this troubleshooting misadventure, it seems like the question of whether Windows 7 service pack 1 may want just ONE of those two registry subkey values set to 0 is no longer a question but a fact as far as AHCI goes.