Error message when you update the SATA controller driver to the MSAHCI driver after you install Windows Vista Service Pack 1: "STOP 0x7B"

Consider the following scenario. You install Windows Vista Service Pack 1 (SP1). At the time of the installation, you install a Serial ATA (SATA) controller driver other than the Microsoft Advanced Host Controller Interface (MSAHCI) driver. Then, after Windows Vista SP1 is installed, you update the existing SATA driver to the MSAHCI driver. However, when you restart the computer after you update the driver, you receive the following stop error message:

This issue occurs because a new feature in Windows Vista SP1 disables the MSAHCI and ATAPI drivers if they are unused. In this scenario, Windows Vista SP1 detects that these drivers are unused at the time of the installation. When you update the existing SATA controller driver to the MSAHCI driver, the MSAHCI driver is enabled, but the ATAPI driver is still disabled. This causes the stop error message.

To work around this issue, enable the ATAPI driver manually before you update the SATA controller driver to the MSAHCI driver. To do this, use one of the following methods.

Method 1: Use the Service Control Manager tool to enable the ATAPI service (recommended)

1. Click Start
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   , type cmd in the Start Search box, and then click cmd in the Programs list.
   
   
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   If you are prompted for an administrator password or confirmation, type your password, or click Continue.
2. Check the current state of the ATAPI service. To do this, at the command prompt, type sc qc atapi, and then press ENTER. You see output that resembles the following:

   SERVICE_NAME: atapi
           TYPE               : 1  KERNEL_DRIVER
           START_TYPE         : 4   DISABLED
           ERROR_CONTROL      : 3   CRITICAL
           BINARY_PATH_NAME   : \SystemRoot\system32\drivers\atapi.sys
           LOAD_ORDER_GROUP   : SCSI Miniport
           TAG                : 33
           DISPLAY_NAME       : IDE Channel
           DEPENDENCIES       :
           SERVICE_START_NAME :
   

3. Change the start type for the ATAPI service from DISABLED to BOOT. To do this, at the command prompt, type sc config atapi start= boot, and then press ENTER.
4. Verify that the ATAPI service is enabled. To do this, at the command prompt, type sc qc atapi, and then press ENTER. You see output that resembles the following:

   SERVICE_NAME: atapi
           TYPE               : 1  KERNEL_DRIVER
           START_TYPE         : 0   BOOT_START
           ERROR_CONTROL      : 3   CRITICAL
           BINARY_PATH_NAME   : \SystemRoot\system32\drivers\atapi.sys
           LOAD_ORDER_GROUP   : SCSI Miniport
           TAG                : 33
           DISPLAY_NAME       : IDE Channel
           DEPENDENCIES       :
           SERVICE_START_NAME :

Method 2: Use the registry to enable the ATAPI service

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

1. Click Start
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   , type regedit in the Start Search box, and then click regedit in the Programs list.
   
   
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   If you are prompted for an administrator password or confirmation, type your password, or click Continue.
2. Locate and then click the following registry entry:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\atapi
3. In the details pane, double-click Start.
4. In Value data box, type 0, and then click OK.
5. In the details pane, double-click ImagePath.
6. In the Value data box, replace \SystemRoot\system32\drivers\atapi.sys with system32\drivers\atapi.sys.
   
   Note Removing the reference to SystemRoot is required when you change the start type to BOOT.
7. Close Registry Editor.

If you receive the stop error message that is mentioned in the "Symptoms" section and you cannot restart the computer, follow these steps to start the computer and to change the start value of the ATAPI service:

1. Start the computer by using the Windows Vista installation media.
2. At the installation screen, press SHIFT+F10 to open a command prompt.
3. Click Start
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   , type regedit in the Start Search box, and then click regedit in the Programs list.
   
   
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   If you are prompted for an administrator password or confirmation, type your password, or click Continue.
4. Locate and then click the following registry subtree:
   HKEY_LOCAL_MACHINE
5. On the File menu, click Load Hive.
6. In the original Windows Vista installation %SystemRoot%\System32\Config folder, click the System file, and then click Open.
7. In the Load Hive dialog box, type test, and then click OK.
   
   Note The HKEY_LOCAL_MACHINE registry subtree of the original Windows Vista installation is loaded as a subkey of the current HKEY_LOCAL_MACHINE registry subtree.
8. Locate and then click the following registry entry:
   HKEY_LOCAL_MACHINE\test\CurrentControlSet\Services\atapi
9. In the details pane, double-click Start, type 0, and then click OK. The ATAPI service start value is now set to BOOT_START.
10. In the details pane, double-click ImagePath.
11. In the Value data box, replace \SystemRoot\system32\drivers\atapi.sys with system32\drivers\atapi.sys.
    
    Note Removing the reference to SystemRoot is required when you change the start type to BOOT.
    
12. In the navigation pane, locate and then click the following registry subkey:
    HKEY_LOCAL_MACHINE\test
13. On the File menu, click Unload Hive to unload the test subkey.
14. Exit Registry Editor.
15. Exit the installation, and then restart the computer from the hard disk.