Windows may crash on boot if asynchronous boot is enabled on some hardware

Applies to: Windows 7 Service Pack 1


Consider the following scenario:

  • You have a system running Windows 7 SP1.
  • Windows is installed onto an SSD drive.
  • The external display is attached via DVI-D.
  • A USB keyboard and mouse are attached to the system.
  • The system is running with asynchronous boot enabled.

In this scenario, the system may crash on boot with a 0x3b error.


This is caused by the system running autochk.exe before all system drivers (including VGA) have been successfully loaded.


Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: 322756 How to back up and restore the registry in Windows.

Disable asynchronous boot through the registry by creating the following registry key:
  1. Click Start, click Run, type regedit in the Open box, and then click OK.
  2. Browse to this path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Pnp (if not already there).
  3. Create a registry key named BootOptions of REG_DWORD type and set its value to 0.