title: How to turn off Windows kernel debugging at boot time?
body: <p>I have a Vista 32 bit machine which I wanted to enable local kernel debugging on.
  In WinDbg I selected File/Kernel Debug and selected the Local tab and clicked ok.
  I got the following message.</p>
  
  <p>The system does not support local kernel debugging.
  ...
  Local kernel debugging is disabled by default in Windows Vista, you must run 'bcdedit -debug on' and reboot to enable it.</p>
  
  <p>I naively followed the instructions and opened an elevated command prompt and typed 'bcdedit -debug on' and the rebooted.</p>
  
  <p>However, on reboot the system hangs when it gets to the logon screen - or just after I type in my username and password. </p>
  
  <p>I suspect what is happening is that because a debugger is enabled, user mode exceptions are being triggered in the kernel debugger process and it is waiting for me to enter some input from an attached debugger??</p>
  
  <p>I was hoping to debug on the actual target machine.</p>
  
  <p>My problem is that every time I boot - whatever F8 boot option I choose - it always either hangs or gets so far and then reboots - and then hangs.</p>
  
  <p>Booting in Safe Mode - gets close to the logon screen and then reboots.
  Same applies for the command line and network boot options.
  Last known good config - hangs too.</p>
  
  <p>Is there any way to change the boot option before Windows loads so that I can turn off kernel debugging. I have only the one boot config which was, in hindsight, my problem - I should have created a copy of the first boot config for my debug boot option.</p>
  
  <p>Unfortunately the system doesn't have a serial port so I can't attempt to debug through that.</p>
  
  <p>The only option I can think of now is to attempt to connect a debugger from a different machine through a USB port. However, don't I need to configure the target PC to accept a debugger on a USB port or will this just work if I get a proper debug USB cable?</p>