Enabling Debug mode causes Windows to hang if no Debugger is connected


Symptoms


On a computer that is running Windows 7 or Windows Server 2008 R2, after installing Debugging Tools for Windows, the Operating System with debug mode enabled may hang if an application throws user-mode exception.

Cause


When Debug mode is enabled and the debugger has not connected due to the user mode exception, the system will hang waiting for a debugger to intervene from the breakpoint.

Resolution


To resolve this problem, disable Debug mode using one of the methods below:

  • Using System Configuration settings
  1. Using keyboard press, Windows Key+R to open Run box
  2. Type MSCONFIG and then press Enter
  3. Select Boot tab and then select Advanced options
  4. Uncheck on the Debug check box
  5. Click on OK
  6. Click on Apply and then OK
  7. Restart the computer
  • Using Command Line Interface
  1. Open an elevated Command prompt
  2. Type the following command and press Enter:
    bcdedit -debug off

  3. Restart the computer

More Information


Note that Windows should not be run in Debug mode permanently. Debug mode is enabled for connecting to Kernel Debug using Debuggers like Debugging Tools for Windows (WinDbg) and must be turned off once the purpose is accomplished.

Some Windows 7 systems might be shipped with DEBUG switch enabled, ensure to disable it.

To download Debugging Tools for Windows and more information, visit the following Microsoft Website:

http://msdn.microsoft.com/en-us/windows/hardware/gg463009.aspx