Error: Debugging Isn't Possible Because a Kernel Debugger is Enabled on the System

When you debug managed code, you might receive the following error message:

Debugging isn't possible because a kernel debugger is enabled on the system

This message occurs when you try to debug managed code:

• on a Windows 7 or Windows Vistasystem that has been started in debug mode.

• the application uses the CLR version CLR 2.0, 3.0, or 3.5.

Solution

To fix this problem

• Upgrade your application to use CLR version 4.0 or 4.5

  —or—

• Disable kernel debugging and debug in Visual Studio.

  —or—

• Debug using the Kernel Debugger instead of Visual Studio.

  —or—

• In the Kernel Debugger, disable user-mode exceptions.

To disable kernel debugging in the current session

• At the command prompt, type:

  Kdbgctrl.exe -d
  

To disable kernel debugging for all sessions (Windows Vista and Windows 7)

1. At the command prompt, type:

   bcdedit /debug off 
   

2. Restart the computer.

To disable kernel debugging for all sessions (other Windows operating systems)

1. Locate boot.ini on your system drive (usually C:\). The boot.ini file might be hidden and read-only. Therefore, you must use the following command to see it:

   dir /ASH
   

2. Open boot.ini using Notepad and remove the following options:

   /debug
   /debugport
   /baudrate
   

3. Restart the computer.

To debug with the Kernel Debugger

1. If the Kernel Debugger is hooked up, you will see a message that asks whether you want to continue to debug. Click the button to continue.

2. You might get a User break exception(Int 3). If this occurs, type the following Kernel Debugger command to continue to debug:

   gn

See Also

Concepts

Debugger Security

Other Resources

Debugging Managed Code